[{"data":1,"prerenderedAt":1356},["ShallowReactive",2],{"questions:human-body-anatomy":3},{"bank":4,"contentHash":1339,"dependencyHashes":1340,"releaseId":1355},{"schemaVersion":5,"conceptId":6,"revision":5,"title":7,"intro":8,"sections":9,"questions":50,"sourceIds":1321,"reviewStatus":1335,"authoring":1336},1,"human-body-anatomy","Human body anatomy: question bank","Seventy questions across ten sections, from straightforward recall to multi-step reasoning that combines facts from several layers of this topic. Every numeric answer is computed and checked in Python; every question has a worked solution, not just an answer.",[10,14,18,22,26,30,34,38,42,46],{"id":11,"title":12,"description":13},"organisation","Cells, tissues, organs, systems","Levels of organisation, the four tissue types, and what makes something an organ.",{"id":15,"title":16,"description":17},"skeleton","The skeleton","Bone counts, the axial and appendicular skeleton, famous bones, and growth.",{"id":19,"title":20,"description":21},"joints","Joints","Joint types, cartilage, ligaments and tendons.",{"id":23,"title":24,"description":25},"muscles","Muscles","The three muscle types, antagonistic pairs and the diaphragm.",{"id":27,"title":28,"description":29},"organs","Organs: size and position","Where the main organs sit, their sizes, and the body cavities.",{"id":31,"title":32,"description":33},"skin-senses","Skin and the senses","Skin layers and the organs behind sight, hearing and other senses.",{"id":35,"title":36,"description":37},"symmetry","Symmetry","What is paired, what is not, and genuine edge cases like situs inversus.",{"id":39,"title":40,"description":41},"measuring","Measuring the body","Pulse, height, arm span, hand spans and what class data can and cannot show.",{"id":43,"title":44,"description":45},"history-imaging","History and imaging","Sushruta, Galen, Vesalius, and the four ways of seeing inside a living body.",{"id":47,"title":48,"description":49},"mechanics-animals","Mechanics and animal comparisons","Levers, scaling laws, and how other animals use the same body plan differently.",[51,75,93,113,131,143,163,176,196,208,227,237,246,259,278,290,300,318,336,354,373,391,409,427,445,464,482,492,510,528,546,565,583,594,611,623,641,652,671,689,708,718,736,754,764,783,802,820,835,853,871,882,900,918,935,953,972,985,996,1005,1023,1032,1041,1060,1078,1088,1106,1124,1143,1161,1179,1191,1210,1219,1237,1256,1275,1293,1312],{"id":52,"section":11,"level":53,"prompt":54,"check":55,"hints":71,"solution":73,"skills":74},"human-body-anatomy.q001","foundation","Put these in order from smallest to largest: organ, cell, tissue, organ system.",{"kind":56,"options":57,"correct":70},"choice",[58,61,64,67],{"id":59,"label":60},"a","cell → tissue → organ → organ system",{"id":62,"label":63},"b","tissue → cell → organ → organ system",{"id":65,"label":66},"c","cell → organ → tissue → organ system",{"id":68,"label":69},"d","organ → tissue → cell → organ system",[59],[72],"A cell is the smallest living unit.","Cells of one kind make a tissue; several tissues together make an organ; organs sharing a task make an organ system. So: cell → tissue → organ → organ system.",[11],{"id":76,"section":11,"level":53,"prompt":77,"check":78,"hints":89,"solution":91,"skills":92},"human-body-anatomy.q002","What is an organ?",{"kind":56,"options":79,"correct":88},[80,82,84,86],{"id":59,"label":81},"The smallest living unit",{"id":62,"label":83},"A structure made of more than one tissue, doing one main job",{"id":65,"label":85},"A group of organ systems",{"id":68,"label":87},"Any part of the body you can see",[62],[90],"Think of the heart: what is it made of?","An organ is built from several kinds of tissue working together for one main job — the heart contains muscle, connective and nervous tissue, for example.",[11],{"id":94,"section":11,"level":95,"prompt":96,"check":97,"hints":108,"solution":110,"skills":111},"human-body-anatomy.q003","core","Blood is classified as which type of tissue?",{"kind":56,"options":98,"correct":107},[99,101,103,105],{"id":59,"label":100},"Epithelial",{"id":62,"label":102},"Connective",{"id":65,"label":104},"Muscle",{"id":68,"label":106},"It is not a tissue at all",[62],[109],"Connective tissue is defined by the material between its cells, not by what that material is.","Blood is a connective tissue: its cells (red cells, white cells, platelets) are suspended in a liquid — plasma — instead of the solid material found in bone or cartilage. Scattered cells with a lot of material between them is the defining feature of every connective tissue.",[112],"tissues",{"id":114,"section":11,"level":95,"prompt":115,"check":116,"hints":127,"solution":129,"skills":130},"human-body-anatomy.q004","Why is the femur classed as an organ rather than just \"a piece of tissue\"?",{"kind":56,"options":117,"correct":126},[118,120,122,124],{"id":59,"label":119},"Because it is very large",{"id":62,"label":121},"Because it contains several different tissues: bone, cartilage, marrow, blood vessels and nerves",{"id":65,"label":123},"Because it can move on its own",{"id":68,"label":125},"Because it has a Latin name",[62],[128],"An organ is defined by combining more than one tissue type, not by size.","Size has nothing to do with the definition. A single bone contains bone tissue, cartilage at its ends, marrow inside, plus blood vessels and nerves — several different tissues working together, which is exactly what makes it an organ.",[11],{"id":132,"section":11,"level":95,"prompt":133,"check":134,"hints":138,"solution":140,"skills":141},"human-body-anatomy.q005","About how many trillion cells does the best current estimate give for an adult human body (to the nearest whole trillion)?",{"kind":135,"answer":136,"tolerance":5,"unit":137},"number",37,"trillion",[139],"The published estimate is about 37.2 trillion.","The best-known published estimate (Bianconi and colleagues, 2013) gives about 37.2 trillion cells, which rounds to 37 trillion. It is an estimate built organ by organ, not an actual count.",[142],"cell count",{"id":144,"section":11,"level":145,"prompt":146,"check":147,"hints":158,"solution":160,"skills":161},"human-body-anatomy.q006","stretch","Why do scientists describe the \"37.2 trillion cells\" figure as an estimate rather than a measurement?",{"kind":56,"options":148,"correct":157},[149,151,153,155],{"id":59,"label":150},"Because nobody has ever tried to work it out",{"id":62,"label":152},"Because it is built up from typical cell sizes and organ volumes, not from counting every cell directly",{"id":65,"label":154},"Because the true number is unknowable in principle",{"id":68,"label":156},"Because different people always have exactly the same number of cells",[62],[159],"Think about how you would even begin to count something that small in something that large.","You cannot count cells one by one across an entire living body. The figure comes from measuring typical cell sizes and organ volumes and combining them — a careful, useful estimate, but not a direct count, and it varies with body size.",[142,162],"scientific method",{"id":164,"section":11,"level":95,"prompt":165,"check":166,"hints":172,"solution":174,"skills":175},"human-body-anatomy.q007","Name the four main tissue types the human body is built from.",{"kind":167,"accept":168},"text",[169,170,171],"epithelial, connective, muscle, nervous","epithelial connective muscle nervous","connective, epithelial, muscle, nervous",[173],"They cover\u002Fline, support\u002Ftransport, shorten, and signal.","The four tissue types are epithelial (covers and lines), connective (supports, binds and transports), muscle (shortens to move or squeeze) and nervous (senses and signals).",[112],{"id":177,"section":11,"level":178,"prompt":179,"check":180,"hints":191,"solution":193,"skills":194},"human-body-anatomy.q008","challenge","A doctor examining an unfamiliar tissue sample sees cells packed tightly together in sheets, with almost no material between them. Which tissue type is this most likely to be, and why?",{"kind":56,"options":181,"correct":190},[182,184,186,188],{"id":59,"label":183},"Connective tissue, because it supports things",{"id":62,"label":185},"Epithelial tissue, because epithelial cells are packed tightly with little between them",{"id":65,"label":187},"Muscle tissue, because muscle cells are long",{"id":68,"label":189},"Nervous tissue, because nerves are everywhere",[62],[192],"Which tissue type is defined by having almost nothing between its cells?","Epithelial tissue is defined by cells packed tightly in sheets with almost no gap between them, unlike connective tissue where the material between cells is the whole point. The clue in the description points directly at epithelial tissue.",[112,195],"reasoning",{"id":197,"section":15,"level":53,"prompt":198,"check":199,"hints":203,"solution":205,"skills":206},"human-body-anatomy.q009","How many bones does a typical adult human have?",{"kind":135,"answer":200,"tolerance":201,"unit":202},206,0,"bones",[204],"It is a famous round-ish number, just over 200.","A typical adult has **206** bones: 80 axial (skull, spine, ribs, breastbone) plus 126 appendicular (limbs and girdles).",[207],"skeleton counts",{"id":209,"section":15,"level":53,"prompt":210,"check":211,"hints":222,"solution":224,"skills":225},"human-body-anatomy.q010","Why does a newborn baby have more bones than an adult?",{"kind":56,"options":212,"correct":221},[213,215,217,219],{"id":59,"label":214},"Babies grow extra bones that later dissolve away",{"id":62,"label":216},"Many separate bones and pieces of cartilage fuse together as a child grows",{"id":65,"label":218},"The counting method used for babies is different",{"id":68,"label":220},"Babies’ bones break more often",[62],[223],"Think about the skull, the sacrum and the coccyx.","A newborn has roughly 300 separate bones and cartilages. About 94 of these fuse together into single bones as a child grows — most clearly in the skull, the sacrum and the coccyx — leaving 206 in an adult.",[207,226],"growth",{"id":228,"section":15,"level":95,"prompt":229,"check":230,"hints":232,"solution":234,"skills":235},"human-body-anatomy.q011","The axial skeleton has 22 skull bones, 6 ear ossicles, 1 hyoid bone, 26 vertebral column bones, 24 ribs and 1 sternum. What is the total?",{"kind":135,"answer":231,"tolerance":201,"unit":202},80,[233],"Add them one pair at a time rather than all at once.","22 + 6 + 1 + 26 + 24 + 1 = **80**, the axial skeleton.",[207,236],"arithmetic",{"id":238,"section":15,"level":95,"prompt":239,"check":240,"hints":242,"solution":244,"skills":245},"human-body-anatomy.q012","One hand has 8 carpals, 5 metacarpals and 14 phalanges. How many bones is that in one hand?",{"kind":135,"answer":241,"tolerance":201,"unit":202},27,[243],"Add the three groups.","8 + 5 + 14 = **27** bones in one hand.",[207,236],{"id":247,"section":15,"level":145,"prompt":248,"check":249,"hints":253,"solution":256,"skills":257},"human-body-anatomy.q013","Two hands (27 bones each) and two feet (26 bones each) together hold what percentage of the 206-bone skeleton, to one decimal place?",{"kind":135,"answer":250,"tolerance":251,"unit":252},51.5,0.1,"%",[254,255],"First find the total for two hands and two feet: 54 + 52.","Then divide by the total skeleton and multiply by 100.","Two hands and two feet: (2 × 27) + (2 × 26) = 106. As a percentage of 206: 106 ÷ 206 × 100 = **51.5%** — just over half of all your bones.",[207,258],"percentages",{"id":260,"section":15,"level":95,"prompt":261,"check":262,"hints":273,"solution":275,"skills":276},"human-body-anatomy.q014","Which of these belongs to the axial skeleton rather than the appendicular skeleton?",{"kind":56,"options":263,"correct":272},[264,266,268,270],{"id":59,"label":265},"The collarbone",{"id":62,"label":267},"The shoulder blade",{"id":65,"label":269},"The sternum",{"id":68,"label":271},"The femur",[65],[274],"The axial skeleton is the central column: skull, spine, ribs, breastbone.","The sternum (breastbone) is part of the central axial column. The collarbone, shoulder blade and femur are all part of the 126-bone appendicular skeleton — the limbs and their girdles.",[277],"skeleton anatomy",{"id":279,"section":15,"level":53,"prompt":280,"check":281,"hints":285,"solution":287,"skills":288},"human-body-anatomy.q015","A person is 160 cm tall. Using femur ≈ height × 0.267, estimate their femur length in cm to one decimal place.",{"kind":135,"answer":282,"tolerance":283,"unit":284},42.7,0.2,"cm",[286],"Multiply 160 by 0.267.","160 × 0.267 = **42.7 cm**.",[289,236],"femur ratio",{"id":291,"section":15,"level":145,"prompt":292,"check":293,"hints":296,"solution":298,"skills":299},"human-body-anatomy.q016","A femur measures 45 cm. Using height ≈ femur ÷ 0.267, estimate that person’s height in cm to one decimal place.",{"kind":135,"answer":294,"tolerance":295,"unit":284},168.5,0.3,[297],"Divide 45 by 0.267, not the other way round.","45 ÷ 0.267 ≈ **168.5 cm**. This is the same ratio used in forensic anthropology to estimate a person’s height from a single recovered bone.",[289,236],{"id":301,"section":15,"level":53,"prompt":302,"check":303,"hints":314,"solution":316,"skills":317},"human-body-anatomy.q017","Where is the smallest bone in the human body?",{"kind":56,"options":304,"correct":313},[305,307,309,311],{"id":59,"label":306},"In the little finger",{"id":62,"label":308},"In the nose",{"id":65,"label":310},"Inside the ear",{"id":68,"label":312},"In the big toe",[65],[315],"It is one of three tiny bones in the middle ear.","The stapes (stirrup), about 3.0 mm long, sits deep in the middle ear and is the smallest bone in the human body.",[277],{"id":319,"section":15,"level":95,"prompt":320,"check":321,"hints":332,"solution":334,"skills":335},"human-body-anatomy.q018","Roughly how many bones does an adult’s spine (vertebral column) have?",{"kind":56,"options":322,"correct":331},[323,325,327,329],{"id":59,"label":324},"12",{"id":62,"label":326},"18",{"id":65,"label":328},"26",{"id":68,"label":330},"33",[65],[333],"It is the sum of the movable vertebrae plus the fused sacrum and coccyx.","An adult spine has **26** bones: 24 movable (7 neck, 12 chest, 5 lower back) plus the fused sacrum and coccyx counted as one bone each. A newborn’s spine has 33 separate pieces before fusion.",[207],{"id":337,"section":15,"level":178,"prompt":338,"check":339,"hints":350,"solution":352,"skills":353},"human-body-anatomy.q019","Why are lumbar (lower back) vertebrae noticeably larger than cervical (neck) vertebrae?",{"kind":56,"options":340,"correct":349},[341,343,345,347],{"id":59,"label":342},"They contain more marrow",{"id":62,"label":344},"They carry the weight of everything above them, while neck vertebrae carry only the head",{"id":65,"label":346},"They have ribs attached, unlike neck vertebrae",{"id":68,"label":348},"There is no real size difference",[62],[351],"Think about how much weight passes through each part of the spine.","Vertebra size follows load. Neck vertebrae support only the head; lumbar vertebrae support the entire weight of the head, arms, chest and everything above them, so they are built noticeably bigger and thicker to carry it.",[277,195],{"id":355,"section":15,"level":145,"prompt":356,"check":357,"hints":368,"solution":370,"skills":371},"human-body-anatomy.q020","Which statement about rib pairs is correct?",{"kind":56,"options":358,"correct":367},[359,361,363,365],{"id":59,"label":360},"Everyone has 12 pairs, but men have one fewer pair than women",{"id":62,"label":362},"Everyone has 12 pairs: 7 true, 3 false and 2 floating",{"id":65,"label":364},"The number of rib pairs varies enormously between individuals",{"id":68,"label":366},"Ribs are part of the appendicular skeleton",[62],[369],"The \"men have one fewer rib\" claim is a well-known myth.","Everyone has 12 pairs of ribs: 7 true pairs reaching the breastbone directly, 3 false pairs joining the cartilage above, and 2 floating pairs anchored only at the spine. The \"one fewer rib\" claim about men is a myth with no basis in anatomy.",[277,372],"misconceptions",{"id":374,"section":19,"level":53,"prompt":375,"check":376,"hints":387,"solution":389,"skills":390},"human-body-anatomy.q021","Which joint type allows movement in every direction, including rotation?",{"kind":56,"options":377,"correct":386},[378,380,382,384],{"id":59,"label":379},"Hinge",{"id":62,"label":381},"Ball-and-socket",{"id":65,"label":383},"Pivot",{"id":68,"label":385},"Fixed",[62],[388],"Think of the shoulder or hip.","A ball-and-socket joint (shoulder, hip) has a rounded head sitting in a cup, allowing movement in every direction plus rotation — the freest joint type.",[19],{"id":392,"section":19,"level":53,"prompt":393,"check":394,"hints":405,"solution":407,"skills":408},"human-body-anatomy.q022","Which joint type lets you shake your head to mean \"no\"?",{"kind":56,"options":395,"correct":404},[396,398,400,402],{"id":59,"label":397},"A hinge joint",{"id":62,"label":399},"A ball-and-socket joint",{"id":65,"label":401},"A pivot joint",{"id":68,"label":403},"A fixed joint",[65],[406],"This joint allows rotation only, at the top of the neck.","The first neck bone pivots on a peg from the second neck bone — a pivot joint that allows rotation only. Nodding \"yes\" uses a different, rocking joint one level higher.",[19],{"id":410,"section":19,"level":95,"prompt":411,"check":412,"hints":423,"solution":425,"skills":426},"human-body-anatomy.q023","What does a ligament connect, and what does a tendon connect?",{"kind":56,"options":413,"correct":422},[414,416,418,420],{"id":59,"label":415},"Ligament: muscle to bone. Tendon: bone to bone.",{"id":62,"label":417},"Ligament: bone to bone. Tendon: muscle to bone.",{"id":65,"label":419},"Both connect muscle to muscle.",{"id":68,"label":421},"Both connect bone to bone.",[62],[424],"One limits movement; the other transmits a pull.","A ligament joins bone to bone and limits how far a joint can travel. A tendon joins muscle to bone and transmits the muscle’s pull onto the skeleton. Both are made mostly of collagen, which is why they can be confused.",[19,372],{"id":428,"section":19,"level":95,"prompt":429,"check":430,"hints":441,"solution":443,"skills":444},"human-body-anatomy.q024","What is the special job of the saddle joint at the base of the thumb?",{"kind":56,"options":431,"correct":440},[432,434,436,438],{"id":59,"label":433},"It stops the thumb moving at all",{"id":62,"label":435},"It lets the thumb swing across the palm and touch each fingertip (opposition)",{"id":65,"label":437},"It only allows the thumb to bend, like a finger",{"id":68,"label":439},"It connects the thumb directly to the elbow",[62],[442],"This joint is why humans can grip tools precisely.","The saddle joint at the base of the thumb allows opposition — the thumb can swing across the palm and touch each fingertip — which is essential for gripping a pen, a tool or a cricket ball.",[19],{"id":446,"section":19,"level":145,"prompt":447,"check":448,"hints":459,"solution":461,"skills":462},"human-body-anatomy.q025","A chicken bone soaked for several days in vinegar becomes bendy enough to tie in a knot. What has the vinegar dissolved out?",{"kind":56,"options":449,"correct":458},[450,452,454,456],{"id":59,"label":451},"The collagen",{"id":62,"label":453},"The mineral (calcium phosphate)",{"id":65,"label":455},"The marrow",{"id":68,"label":457},"The water",[62],[460],"What is left behind is flexible, which tells you what was removed.","The acid dissolves out the mineral (about 65% of dry bone), leaving mostly collagen, which is flexible enough to tie in a knot. Baking a bone instead destroys the collagen and leaves something hard but crumbly — the opposite experiment.",[463],"bone composition",{"id":465,"section":19,"level":178,"prompt":466,"check":467,"hints":478,"solution":480,"skills":481},"human-body-anatomy.q026","A joint has a shallow socket and a very large range of movement, but dislocates more easily than most other joints. Which joint is this, and why does the trade-off exist?",{"kind":56,"options":468,"correct":477},[469,471,473,475],{"id":59,"label":470},"The knee, because it is a hinge joint",{"id":62,"label":472},"The shoulder, because a shallow ball-and-socket favours range of movement over stability",{"id":65,"label":474},"The hip, because its socket is very deep",{"id":68,"label":476},"The elbow, because it only bends in one plane",[62],[479],"Compare the shoulder’s socket depth with the hip’s.","The shoulder is a ball-and-socket joint with a shallow socket, which trades stability for an enormous range of movement — exactly why it is the most commonly dislocated joint in the body, unlike the hip, whose deep socket favours stability over range.",[19,195],{"id":483,"section":19,"level":95,"prompt":484,"check":485,"hints":488,"solution":490,"skills":491},"human-body-anatomy.q027","How many main types of joint (by movement) are usually taught: hinge, ball-and-socket, pivot, gliding, saddle and fixed?",{"kind":135,"answer":486,"tolerance":201,"unit":487},6,"types",[489],"Count the list given in the question.","Six joint types are commonly taught: hinge, ball-and-socket, pivot, gliding, saddle and fixed — each allowing a different kind and amount of movement.",[19],{"id":493,"section":19,"level":53,"prompt":494,"check":495,"hints":506,"solution":508,"skills":509},"human-body-anatomy.q028","What is cartilage?",{"kind":56,"options":496,"correct":505},[497,499,501,503],{"id":59,"label":498},"A type of muscle",{"id":62,"label":500},"A smooth, rubbery connective tissue that cushions joints and shapes the nose and ear",{"id":65,"label":502},"The fluid inside a joint",{"id":68,"label":504},"A kind of bone marrow",[62],[507],"Press your nose or the outer part of your ear — that is cartilage.","Cartilage is a smooth, rubbery connective tissue that caps bone ends inside joints, cushions them, and also shapes structures like the nose and outer ear, which are cartilage all the way through.",[19,112],{"id":511,"section":23,"level":53,"prompt":512,"check":513,"hints":524,"solution":526,"skills":527},"human-body-anatomy.q029","Which statement about muscles is true?",{"kind":56,"options":514,"correct":523},[515,517,519,521],{"id":59,"label":516},"Muscles can push and pull equally well",{"id":62,"label":518},"Muscles can only pull, so they work in opposing pairs",{"id":65,"label":520},"Muscles push bones apart; gravity pulls them back",{"id":68,"label":522},"Only leg muscles work in pairs",[62],[525],"A muscle shortens to pull, then simply goes slack.","A muscle can only shorten to pull; it cannot lengthen to push. To move a joint both ways, a second muscle on the opposite side must pull it back — an antagonistic pair, such as biceps and triceps.",[23,372],{"id":529,"section":23,"level":53,"prompt":530,"check":531,"hints":542,"solution":544,"skills":545},"human-body-anatomy.q030","How many kinds of muscle tissue does the human body have?",{"kind":56,"options":532,"correct":541},[533,535,537,539],{"id":59,"label":534},"One",{"id":62,"label":536},"Two",{"id":65,"label":538},"Three",{"id":68,"label":540},"Five",[65],[543],"Think: skeletal, smooth and one more.","Three: skeletal (voluntary, moves bones), smooth (involuntary, in gut and vessel walls) and cardiac (involuntary, heart only).",[23],{"id":547,"section":23,"level":95,"prompt":548,"check":549,"hints":560,"solution":562,"skills":563},"human-body-anatomy.q031","When you straighten your elbow, which muscle is the agonist (the one doing the work)?",{"kind":56,"options":550,"correct":559},[551,553,555,557],{"id":59,"label":552},"The biceps",{"id":62,"label":554},"The triceps",{"id":65,"label":556},"Both equally",{"id":68,"label":558},"Neither; gravity does it",[62],[561],"The triceps runs down the back of the upper arm.","The triceps pulls the forearm straight, making it the agonist. The biceps is the antagonist, paying out under control so the movement is smooth. Bending the elbow swaps the two roles.",[23,564],"antagonistic pairs",{"id":566,"section":23,"level":95,"prompt":567,"check":568,"hints":579,"solution":581,"skills":582},"human-body-anatomy.q032","Which statement about the diaphragm is correct?",{"kind":56,"options":569,"correct":578},[570,572,574,576],{"id":59,"label":571},"It is smooth muscle, so it is entirely involuntary",{"id":62,"label":573},"It is cardiac muscle, like the heart",{"id":65,"label":575},"It is skeletal muscle that runs automatically but can also be controlled",{"id":68,"label":577},"It is not a muscle, but a sheet of cartilage",[65],[580],"You can hold your breath deliberately, but it also runs while you sleep.","The diaphragm is skeletal muscle — which is exactly why you can hold your breath or blow out a candle — yet it keeps working automatically while you sleep. It forms the floor of the chest cavity.",[23],{"id":584,"section":23,"level":145,"prompt":585,"check":586,"hints":590,"solution":592,"skills":593},"human-body-anatomy.q033","At a resting rate of 70 beats a minute, roughly how many times does the heart beat in one day?",{"kind":135,"answer":587,"tolerance":588,"unit":589},100800,100,"beats",[591],"Multiply 70 by 60 (minutes in an hour) then by 24 (hours in a day).","70 × 60 × 24 = **100,800 beats a day**. Cardiac muscle rests briefly between every single beat and has its own dedicated blood supply, which is how it manages this without ever taking a day off.",[23,236],{"id":595,"section":23,"level":95,"prompt":596,"check":597,"hints":607,"solution":609,"skills":610},"human-body-anatomy.q034","Which type of muscle tissue is found only in the wall of the heart?",{"kind":56,"options":598,"correct":606},[599,601,603,605],{"id":59,"label":600},"Skeletal",{"id":62,"label":602},"Smooth",{"id":65,"label":604},"Cardiac",{"id":68,"label":102},[65],[608],"This one type is unique to one organ.","Cardiac muscle is found nowhere else in the body except the heart wall. It is striped like skeletal muscle but beats on its own rhythm and never tires the way skeletal muscle does.",[23],{"id":612,"section":23,"level":53,"prompt":613,"check":614,"hints":619,"solution":621,"skills":622},"human-body-anatomy.q035","Name the pair of muscles at the front and back of the upper arm that bend and straighten the elbow.",{"kind":167,"accept":615},[616,617,618],"biceps and triceps","biceps triceps","triceps and biceps",[620],"Front of the upper arm bends it; back of the upper arm straightens it.","The biceps (front of the upper arm) bends the elbow, and the triceps (back of the upper arm) straightens it — a classic antagonistic pair.",[23,564],{"id":624,"section":23,"level":178,"prompt":625,"check":626,"hints":637,"solution":639,"skills":640},"human-body-anatomy.q036","Skeletal muscle tires quickly under sustained load, but smooth muscle in the gut can hold a squeeze for a long time. What does this difference mainly reflect?",{"kind":56,"options":627,"correct":636},[628,630,632,634],{"id":59,"label":629},"Smooth muscle is simply bigger",{"id":62,"label":631},"Different muscle types are built for different jobs: fast, strong, tiring movement versus slow, steady, sustained squeezing",{"id":65,"label":633},"Skeletal muscle is not really muscle at all",{"id":68,"label":635},"There is no real difference between them",[62],[638],"Compare what each type is actually used for in the body.","Skeletal muscle is built for fast, strong, voluntary movement, which comes at the cost of tiring quickly. Smooth muscle is built for slow, steady, involuntary squeezing that can be sustained for a long time — different jobs, different designs, both valid trade-offs.",[23,195],{"id":642,"section":23,"level":95,"prompt":643,"check":644,"hints":647,"solution":649,"skills":650},"human-body-anatomy.q037","About what percentage of an adult’s body mass is skeletal muscle?",{"kind":135,"answer":645,"tolerance":646,"unit":252},40,5,[648],"It is close to 40%.","Skeletal muscle makes up roughly 40% of an adult’s body mass — more than the skeleton and internal organs put together.",[23,651],"body composition",{"id":653,"section":27,"level":53,"prompt":654,"check":655,"hints":666,"solution":668,"skills":669},"human-body-anatomy.q038","Where is your heart actually positioned?",{"kind":56,"options":656,"correct":665},[657,659,661,663],{"id":59,"label":658},"On the far left side of the chest",{"id":62,"label":660},"In the middle of the chest, tipped slightly left",{"id":65,"label":662},"On the right side of the chest",{"id":68,"label":664},"Below the lungs, near the stomach",[62],[667],"Most people point too far to the side.","The heart sits in the middle of the chest between the two lungs, tipped only slightly to the left — not out on the side of the chest where most people point.",[670,372],"organ positions",{"id":672,"section":27,"level":53,"prompt":673,"check":674,"hints":685,"solution":687,"skills":688},"human-body-anatomy.q039","Where is your stomach?",{"kind":56,"options":675,"correct":684},[676,678,680,682],{"id":59,"label":677},"Just behind the navel",{"id":62,"label":679},"High on the left, under the ribs",{"id":65,"label":681},"Low in the pelvis",{"id":68,"label":683},"High on the right, under the ribs",[62],[686],"It sits much higher than most people guess.","The stomach sits high on the left side, tucked under the ribs — far above the navel. What is behind the navel is mostly coiled small intestine.",[670,372],{"id":690,"section":27,"level":95,"prompt":691,"check":692,"hints":703,"solution":705,"skills":706},"human-body-anatomy.q040","Which is the largest organ of the human body overall?",{"kind":56,"options":693,"correct":702},[694,696,698,700],{"id":59,"label":695},"The liver",{"id":62,"label":697},"The brain",{"id":65,"label":699},"The skin",{"id":68,"label":701},"The large intestine",[65],[704],"Think about which organ you can see and touch entirely.","The skin, covering 1.5 to 2.0 square metres, is the largest organ overall. The liver (about 1.5 kg) is the largest organ *inside* the body — both statements are true and often confused.",[707,372],"organ sizes",{"id":709,"section":27,"level":95,"prompt":710,"check":711,"hints":714,"solution":716,"skills":717},"human-body-anatomy.q041","The small intestine is about 6.0 m long and the large intestine about 1.5 m. What is their combined length in metres?",{"kind":135,"answer":712,"tolerance":201,"unit":713},7.5,"m",[715],"Add the two lengths.","6.0 + 1.5 = **7.5 m** of intestine, coiled into a space roughly the size of a football.",[707,236],{"id":719,"section":27,"level":95,"prompt":720,"check":721,"hints":732,"solution":734,"skills":735},"human-body-anatomy.q042","Why does the left lung have fewer lobes than the right lung?",{"kind":56,"options":722,"correct":731},[723,725,727,729],{"id":59,"label":724},"The left lung does less work",{"id":62,"label":726},"The heart takes up room on the left, leaving less space",{"id":65,"label":728},"The left lung is damaged by breathing over time",{"id":68,"label":730},"The liver pushes it upwards",[62],[733],"The heart leans to one side.","The heart leans left, so the left lung has a notch scooped out to make room for it: 2 lobes on the left against 3 on the right.",[670,35],{"id":737,"section":27,"level":53,"prompt":738,"check":739,"hints":750,"solution":752,"skills":753},"human-body-anatomy.q043","Where are your kidneys?",{"kind":56,"options":740,"correct":749},[741,743,745,747],{"id":59,"label":742},"A pair at the back, near the lowest ribs",{"id":62,"label":744},"One on each side of the heart",{"id":65,"label":746},"A pair low in the pelvis",{"id":68,"label":748},"Just under the navel, at the front",[59],[751],"They are pressed against the back wall of the belly.","The kidneys are a pair at the back, against the rear wall of the belly, roughly level with the lowest ribs, each about 11 cm long.",[670],{"id":755,"section":27,"level":145,"prompt":756,"check":757,"hints":760,"solution":762,"skills":763},"human-body-anatomy.q044","The stomach holds about 50 mL empty and can stretch to about 1500 mL. How many times bigger is that (full ÷ empty)?",{"kind":135,"answer":758,"tolerance":201,"unit":759},30,"×",[761],"Divide the full volume by the empty volume.","1500 ÷ 50 = **30.0×**. The stomach can stretch to about thirty times its empty volume because its lining is folded into ridges that flatten out as it fills.",[707,236],{"id":765,"section":27,"level":95,"prompt":766,"check":767,"hints":778,"solution":780,"skills":781},"human-body-anatomy.q045","The diaphragm divides which two body cavities?",{"kind":56,"options":768,"correct":777},[769,771,773,775],{"id":59,"label":770},"The cranial cavity and the spinal canal",{"id":62,"label":772},"The thoracic cavity and the abdominal cavity",{"id":65,"label":774},"The abdominal cavity and the pelvic cavity",{"id":68,"label":776},"It does not divide any cavities",[62],[779],"Above it: heart and lungs. Below it: stomach and liver.","The diaphragm is the floor of the thoracic (chest) cavity and the ceiling of the abdominal cavity. Above it are the heart and lungs; below it are the liver, stomach, intestines and other digestive organs.",[782],"cavities",{"id":784,"section":27,"level":145,"prompt":785,"check":786,"hints":797,"solution":799,"skills":800},"human-body-anatomy.q046","A doctor needs to describe the exact position of the pancreas. Which description is most precise and correct?",{"kind":56,"options":787,"correct":796},[788,790,792,794],{"id":59,"label":789},"Somewhere in the belly",{"id":62,"label":791},"Abdominal cavity, lying across the back, behind and below the stomach",{"id":65,"label":793},"In the chest, next to the heart",{"id":68,"label":795},"In the pelvis, next to the bladder",[62],[798],"The pancreas is often forgotten because it lies flat against the back.","The pancreas lies in the abdominal cavity, across the back of the belly, behind and below the stomach, with its head tucked into the curve of the small intestine — a precise, correct anatomical description, unlike the vague \"somewhere in the belly\".",[670,801],"anatomical language",{"id":803,"section":27,"level":178,"prompt":804,"check":805,"hints":816,"solution":818,"skills":819},"human-body-anatomy.q047","Two organs sit largely on the same side (left) of the upper abdomen, under the ribs. Which pair is this?",{"kind":56,"options":806,"correct":815},[807,809,811,813],{"id":59,"label":808},"Liver and kidney",{"id":62,"label":810},"Stomach and spleen",{"id":65,"label":812},"Heart and bladder",{"id":68,"label":814},"Pancreas and bladder",[62],[817],"One is a stretchy digestive bag; the other filters blood and is tucked behind it.","The stomach and the spleen both sit on the left side of the upper abdomen, under the ribs, with the spleen tucked behind the stomach and against the diaphragm — the liver, by contrast, is on the right.",[670,195],{"id":821,"section":31,"level":53,"prompt":822,"check":823,"hints":830,"solution":832,"skills":833},"human-body-anatomy.q048","Skin is made of how many main layers?",{"kind":56,"options":824,"correct":829},[825,826,827,828],{"id":59,"label":534},{"id":62,"label":536},{"id":65,"label":538},{"id":68,"label":540},[65],[831],"Epidermis, dermis, and one more underneath.","Three layers: the epidermis (thin, tough, outer), the dermis (thick, living, with sensors and vessels) and the subcutaneous fat layer beneath.",[834],"skin",{"id":836,"section":31,"level":95,"prompt":837,"check":838,"hints":848,"solution":850,"skills":851},"human-body-anatomy.q049","Which sense organ is described as an optical instrument, with a lens, an aperture and a light-sensitive screen?",{"kind":56,"options":839,"correct":847},[840,842,844,846],{"id":59,"label":841},"The ear",{"id":62,"label":843},"The eye",{"id":65,"label":845},"The nose",{"id":68,"label":699},[62],[849],"A camera uses the same three parts in the same order.","The eye is an optical instrument: a lens focuses light through an aperture (the pupil) onto a light-sensitive layer at the back — exactly the same three parts, in the same order, as a camera.",[852],"senses",{"id":854,"section":31,"level":95,"prompt":855,"check":856,"hints":867,"solution":869,"skills":870},"human-body-anatomy.q050","What passes sound vibrations further inward after they strike the eardrum?",{"kind":56,"options":857,"correct":866},[858,860,862,864],{"id":59,"label":859},"Three tiny bones, including the stapes",{"id":62,"label":861},"The pupil",{"id":65,"label":863},"A fold of skin",{"id":68,"label":865},"The tongue",[59],[868],"One of these three bones is the smallest bone in the body.","Three tiny bones in the middle ear — including the stapes, the smallest bone in the body — pass the eardrum’s vibration inward and concentrate it before it reaches the fluid-filled inner ear.",[852],{"id":872,"section":31,"level":145,"prompt":873,"check":874,"hints":878,"solution":880,"skills":881},"human-body-anatomy.q051","Skin covers about 1.5 to 2.0 square metres. What is the midpoint of that range, in square metres?",{"kind":135,"answer":875,"tolerance":876,"unit":877},1.75,0.05,"m²",[879],"Add the two values and divide by two.","(1.5 + 2.0) ÷ 2 = **1.75 m²**, roughly the size of a large bedsheet.",[834,236],{"id":883,"section":31,"level":53,"prompt":884,"check":885,"hints":896,"solution":898,"skills":899},"human-body-anatomy.q052","Is \"the five senses\" the complete list of everything humans can sense?",{"kind":56,"options":886,"correct":895},[887,889,891,893],{"id":59,"label":888},"Yes, exactly five and no more",{"id":62,"label":890},"No — balance and the sense of limb position are extra examples not on the classic list",{"id":65,"label":892},"No, humans only have three senses",{"id":68,"label":894},"Yes, and animals have the same five",[62],[897],"Close your eyes and touch your nose — what told your hand where to go?","The \"five senses\" is a convenient simplified list, not the whole truth. The ear also senses balance, and sensors in muscles and joints report limb position without needing to look — both are senses beyond the classic five.",[852,372],{"id":901,"section":31,"level":145,"prompt":902,"check":903,"hints":914,"solution":916,"skills":917},"human-body-anatomy.q053","Skin thickness varies a great deal across the body. Which pairing is correct?",{"kind":56,"options":904,"correct":913},[905,907,909,911],{"id":59,"label":906},"Eyelids are thickest; soles are thinnest",{"id":62,"label":908},"Eyelids are thinnest; soles are thickest",{"id":65,"label":910},"All skin is the same thickness everywhere",{"id":68,"label":912},"Palms are thinnest; eyelids are thickest",[62],[915],"Think about which needs to fold constantly and which takes the most pressure.","Eyelids are among the thinnest skin, needing to fold completely many times a minute; soles of the feet are among the thickest, because they bear your full weight with every step. Structure fits function.",[834,195],{"id":919,"section":35,"level":53,"prompt":920,"check":921,"hints":931,"solution":933,"skills":934},"human-body-anatomy.q054","Which of these comes as a matching left-and-right pair in the body?",{"kind":56,"options":922,"correct":930},[923,925,927,928],{"id":59,"label":924},"The heart",{"id":62,"label":926},"The kidneys",{"id":65,"label":695},{"id":68,"label":929},"The stomach",[62],[932],"You have two of these, filtering blood.","The kidneys are a matching pair, one on each side. The heart, liver and stomach are each single organs, positioned off-centre rather than mirrored.",[35],{"id":936,"section":35,"level":95,"prompt":937,"check":938,"hints":949,"solution":951,"skills":952},"human-body-anatomy.q055","Which best describes the human body’s overall symmetry?",{"kind":56,"options":939,"correct":948},[940,942,944,946],{"id":59,"label":941},"Perfectly symmetric, inside and out",{"id":62,"label":943},"Roughly symmetric on the outside; distinctly lopsided inside",{"id":65,"label":945},"Asymmetric both inside and outside",{"id":68,"label":947},"Symmetric inside; asymmetric outside",[62],[950],"Compare two eyes and two ears with one heart and one liver.","Humans are bilaterally symmetric on the outside — matching eyes, ears, arms and legs — but the inside is deliberately lopsided: the heart leans left, the liver sits right, the stomach and spleen sit left.",[35],{"id":954,"section":35,"level":178,"prompt":955,"check":956,"hints":967,"solution":969,"skills":970},"human-body-anatomy.q056","A rare condition called situs inversus mirrors the position of every asymmetric organ (heart right instead of left, liver left instead of right, and so on). Why do many people with this condition have no related health problems?",{"kind":56,"options":957,"correct":966},[958,960,962,964],{"id":59,"label":959},"Because their organs are smaller than usual",{"id":62,"label":961},"Because the whole layout is mirrored consistently, so every connection between organs still lines up correctly",{"id":65,"label":963},"Because only unimportant organs are affected",{"id":68,"label":965},"Because the condition always corrects itself",[62],[968],"Think about what happens if every part of a machine is mirrored together, rather than just one part.","Because the reversal is complete and consistent — every organ flips together — all the connections between organs still match up correctly, the way a fully mirrored machine would still function. This is different from a partial, inconsistent mix-up.",[35,971],"edge cases",{"id":973,"section":35,"level":95,"prompt":974,"check":975,"hints":980,"solution":982,"skills":983},"human-body-anatomy.q057","What single word describes an organ that comes as two identical copies, one on each side of the body?",{"kind":167,"accept":976},[977,978,979],"pair","a pair","paired",[981],"Eyes, ears, lungs, kidneys all fit this pattern.","Such organs are described as coming \"in a pair\" — eyes, ears, lungs and kidneys are the clearest human examples.",[35,984],"vocabulary",{"id":986,"section":39,"level":53,"prompt":987,"check":988,"hints":991,"solution":993,"skills":994},"human-body-anatomy.q058","A pulse is counted for 15 seconds and 18 beats are recorded. What is the pulse rate in beats per minute?",{"kind":135,"answer":989,"tolerance":201,"unit":990},72,"bpm",[992],"Multiply the 15-second count by 4.","18 × 4 = **72 bpm**. Counting for 15 seconds and multiplying by 4 is the standard classroom method for measuring pulse.",[995,236],"measurement",{"id":997,"section":39,"level":95,"prompt":998,"check":999,"hints":1000,"solution":1002,"skills":1003},"human-body-anatomy.q059","In a class of 15 pupils, the mean height was 148.9 cm and the mean arm span was 149.0 cm. What was the difference between the two means, in cm?",{"kind":135,"answer":251,"tolerance":251,"unit":284},[1001],"Subtract the smaller mean from the larger one.","149.0 − 148.9 = **0.1 cm** — a very small gap, showing the Vitruvian \"height equals arm span\" rule holding up well on average.",[995,1004],"mean",{"id":1006,"section":39,"level":145,"prompt":1007,"check":1008,"hints":1019,"solution":1021,"skills":1022},"human-body-anatomy.q060","In that same class, every pupil’s arm span was within 2 cm of their own height, even though the range of individual differences was 4 cm end to end. What does this show?",{"kind":56,"options":1009,"correct":1018},[1010,1012,1014,1016],{"id":59,"label":1011},"The rule is completely false",{"id":62,"label":1013},"A rule can be true on average without being exact for every individual",{"id":65,"label":1015},"The measurements must be wrong",{"id":68,"label":1017},"Arm span is always more reliable than height",[62],[1020],"The class mean matched almost exactly. Did every individual match exactly too?","This is the key distinction between an average and an individual result: the rule held very well for the group, and only approximately for each person within it. Both facts are true at the same time, and this is not a contradiction.",[995,195],{"id":1024,"section":39,"level":95,"prompt":1025,"check":1026,"hints":1028,"solution":1030,"skills":1031},"human-body-anatomy.q061","A class’s resting mean pulse was 81.3 bpm and their mean pulse after mild exercise was 98.9 bpm. What was the mean rise, in bpm?",{"kind":135,"answer":1027,"tolerance":251,"unit":990},17.6,[1029],"Subtract resting mean from after-exercise mean.","98.9 − 81.3 = **17.6 bpm** average rise, though individual rises varied from 4 to 28 bpm.",[995,1004],{"id":1033,"section":39,"level":53,"prompt":1034,"check":1035,"hints":1037,"solution":1039,"skills":1040},"human-body-anatomy.q062","A desk is 120 cm long. A pupil’s hand span is 20 cm. How many hand spans long is the desk?",{"kind":135,"answer":486,"tolerance":251,"unit":1036},"spans",[1038],"Divide the desk length by the hand span.","120 ÷ 20 = **6.0 hand spans**.",[995,236],{"id":1042,"section":39,"level":145,"prompt":1043,"check":1044,"hints":1055,"solution":1057,"skills":1058},"human-body-anatomy.q063","Two pupils measure the same 120 cm desk in their own hand spans: one has a 16 cm span, the other a 22 cm span. Which is true?",{"kind":56,"options":1045,"correct":1054},[1046,1048,1050,1052],{"id":59,"label":1047},"They will get the same number of spans, since it is the same desk",{"id":62,"label":1049},"The pupil with the smaller hand span will count a bigger number of spans",{"id":65,"label":1051},"The pupil with the smaller hand span will count a smaller number of spans",{"id":68,"label":1053},"Hand-span measuring cannot work with two different pupils",[62],[1056],"A smaller unit means more of them are needed to cover the same length.","A smaller hand span covers less of the desk with each measure, so more of them are needed: 120 ÷ 16 = 7.5 spans versus 120 ÷ 22 = 5.5 spans for the larger hand. The desk has not changed — the measuring unit has.",[995,1059,195],"units",{"id":1061,"section":39,"level":178,"prompt":1062,"check":1063,"hints":1074,"solution":1076,"skills":1077},"human-body-anatomy.q064","Why did standard units like the centimetre eventually replace body-based units like the cubit and the hand span, for scientific and trade purposes?",{"kind":56,"options":1064,"correct":1073},[1065,1067,1069,1071],{"id":59,"label":1066},"Body-based units were too complicated to learn",{"id":62,"label":1068},"A body-based unit changes size from person to person, so it cannot mean exactly the same thing for everyone",{"id":65,"label":1070},"Body-based units were banned by law everywhere",{"id":68,"label":1072},"There was no real reason; it was simply fashion",[62],[1075],"Think about what a unit needs to do to be useful across a whole country or the whole world.","A useful standard unit must mean exactly the same thing for everyone, everywhere. A body-based unit is convenient (always available) but inconsistent (it varies with whoever is measuring), which is precisely the problem a centrally defined, fixed unit like the centimetre solves.",[995,1059,195],{"id":1079,"section":43,"level":53,"prompt":1080,"check":1081,"hints":1083,"solution":1085,"skills":1086},"human-body-anatomy.q065","Vesalius published his corrected human anatomy in 1543. In which century was this?",{"kind":135,"answer":1082,"tolerance":201},16,[1084],"Years 1501-1600 are the 16th century.","1543 falls in the 16th century (the 1500s).",[1087],"history",{"id":1089,"section":43,"level":95,"prompt":1090,"check":1091,"hints":1102,"solution":1104,"skills":1105},"human-body-anatomy.q066","Why did Galen’s anatomy, built mainly from animal dissection, contain errors that persisted for centuries?",{"kind":56,"options":1092,"correct":1101},[1093,1095,1097,1099],{"id":59,"label":1094},"He never dissected anything at all",{"id":62,"label":1096},"Human dissection was banned in his time, so his animal-based conclusions were later copied as fact without being re-checked",{"id":65,"label":1098},"He deliberately invented false information",{"id":68,"label":1100},"His work was lost and later reconstructed incorrectly",[62],[1103],"Roman law of his time forbade human dissection.","Galen worked mainly from animals because Roman law banned human dissection in his time. His careful, evidence-based (but animal-based) conclusions were later copied as settled fact for centuries without being independently re-checked against real human bodies.",[1087,162],{"id":1107,"section":43,"level":95,"prompt":1108,"check":1109,"hints":1120,"solution":1122,"skills":1123},"human-body-anatomy.q067","What was the key method Vesalius used that Galen could not?",{"kind":56,"options":1110,"correct":1119},[1111,1113,1115,1117],{"id":59,"label":1112},"X-ray imaging",{"id":62,"label":1114},"Direct dissection of real human bodies",{"id":65,"label":1116},"Computer modelling",{"id":68,"label":1118},"Interviewing patients",[62],[1121],"This became legally possible in parts of Europe by his time.","Vesalius based his 1543 work on his own direct dissections of real human bodies, which had become more accessible for study in parts of Europe — allowing him to check, and correct, hundreds of Galen’s animal-based claims.",[1087],{"id":1125,"section":43,"level":95,"prompt":1126,"check":1127,"hints":1138,"solution":1140,"skills":1141},"human-body-anatomy.q068","Put these four imaging methods in the order they were invented or first demonstrated: CT, MRI, ultrasound, X-ray.",{"kind":56,"options":1128,"correct":1137},[1129,1131,1133,1135],{"id":59,"label":1130},"X-ray, ultrasound, CT, MRI",{"id":62,"label":1132},"MRI, CT, ultrasound, X-ray",{"id":65,"label":1134},"Ultrasound, X-ray, MRI, CT",{"id":68,"label":1136},"CT, X-ray, ultrasound, MRI",[59],[1139],"X-ray came first, in 1895.","X-ray (1895), then ultrasound (1950s), then CT (1971, first patient scan) and MRI (1973). Each one takes something that can pass through the body and reads what comes out the other side.",[1087,1142],"imaging",{"id":1144,"section":43,"level":145,"prompt":1145,"check":1146,"hints":1157,"solution":1159,"skills":1160},"human-body-anatomy.q069","Which imaging method is chosen for a suspected broken wrist, and why?",{"kind":56,"options":1147,"correct":1156},[1148,1150,1152,1154],{"id":59,"label":1149},"MRI, because it is the most detailed",{"id":62,"label":1151},"X-ray, because bone absorbs radiation strongly and shows up clearly, quickly and cheaply",{"id":65,"label":1153},"Ultrasound, because it works well through bone",{"id":68,"label":1155},"CT, because it is always the first choice",[62],[1158],"Speed, cost and \"does it show bone well\" all matter here.","X-ray is fast, cheap and excellent at showing bone, because dense bone absorbs far more radiation than soft tissue, creating a clear shadow. MRI and CT are reserved for situations needing more detail or three-dimensional information.",[1142,195],{"id":1162,"section":43,"level":178,"prompt":1163,"check":1164,"hints":1175,"solution":1177,"skills":1178},"human-body-anatomy.q070","What physical property does an X-ray image actually map?",{"kind":56,"options":1165,"correct":1174},[1166,1168,1170,1172],{"id":59,"label":1167},"Temperature of each tissue",{"id":62,"label":1169},"How much radiation different tissues absorb",{"id":65,"label":1171},"The colour of each organ",{"id":68,"label":1173},"Blood flow speed",[62],[1176],"Bone blocks more of the beam than soft tissue does.","An X-ray image is a map of how much radiation passes straight through different tissues — dense bone absorbs much more than soft tissue, so it casts a strong shadow. It is a shadow picture, not a photograph of colour.",[1142,195],{"id":1180,"section":43,"level":53,"prompt":1181,"check":1182,"hints":1187,"solution":1189,"skills":1190},"human-body-anatomy.q071","Name the ancient Indian surgical text traditionally dated to around 600 BCE.",{"kind":167,"accept":1183},[1184,1185,1186],"sushruta samhita","the sushruta samhita","sushrita samhita",[1188],"It describes about 121 surgical instruments.","The **Sushruta Samhita**, traditionally dated to around 600 BCE, describes detailed surgical knowledge including nose reconstruction, and about 121 surgical instruments.",[1087],{"id":1192,"section":47,"level":95,"prompt":1193,"check":1194,"hints":1205,"solution":1207,"skills":1208},"human-body-anatomy.q072","Bending the elbow with the biceps is an example of which class of lever?",{"kind":56,"options":1195,"correct":1204},[1196,1198,1200,1202],{"id":59,"label":1197},"First class",{"id":62,"label":1199},"Second class",{"id":65,"label":1201},"Third class",{"id":68,"label":1203},"Not a lever at all",[65],[1206],"The order is fulcrum, then effort, then load.","The elbow is the fulcrum, the biceps (effort) pulls close to it, and the hand (load) is far out — a third-class lever, trading force for speed and range. Almost every limb movement uses this same class.",[1209],"levers",{"id":1211,"section":47,"level":95,"prompt":1212,"check":1213,"hints":1215,"solution":1217,"skills":1218},"human-body-anatomy.q073","A muscle attaches 4 cm from a joint; the load is 32 cm from the same joint. What is the ratio of these distances?",{"kind":135,"answer":1214,"tolerance":201,"unit":759},8,[1216],"Divide the larger distance by the smaller.","32 ÷ 4 = **8.0**. The muscle must pull about 8.0 times harder than the load, but the load moves 8.0 times further for the same muscle shortening.",[1209,236],{"id":1220,"section":47,"level":145,"prompt":1221,"check":1222,"hints":1233,"solution":1235,"skills":1236},"human-body-anatomy.q074","Rising onto your toes uses which class of lever, and what does that class of lever multiply?",{"kind":56,"options":1223,"correct":1232},[1224,1226,1228,1230],{"id":59,"label":1225},"First class; multiplies nothing",{"id":62,"label":1227},"Second class; multiplies force, like a wheelbarrow",{"id":65,"label":1229},"Third class; multiplies speed only",{"id":68,"label":1231},"Second class; multiplies speed, like the elbow",[62],[1234],"Fulcrum, load, then effort, in that order along the foot.","Fulcrum (ball of the foot), load (body weight) in the middle, effort (calf muscle) at the far end — a second-class lever, the same arrangement as a wheelbarrow, which multiplies force rather than speed.",[1209],{"id":1238,"section":47,"level":178,"prompt":1239,"check":1240,"hints":1251,"solution":1253,"skills":1254},"human-body-anatomy.q075","If every linear dimension of an animal doubles with the same body proportions, strength (cross-sectional area) rises by 2² = 4× while mass (volume) rises by 2³ = 8×. What does this predict for a much larger land animal’s leg bones?",{"kind":56,"options":1241,"correct":1250},[1242,1244,1246,1248],{"id":59,"label":1243},"They should look exactly like a scaled-up copy, same proportions",{"id":62,"label":1245},"They should be proportionally thicker, to cope with greater stress per unit of bone",{"id":65,"label":1247},"They should be proportionally thinner",{"id":68,"label":1249},"Scaling laws do not apply to living things",[62],[1252],"Mass grows faster than strength as size increases.","Because mass grows faster than strength as an animal scales up, a larger animal needs proportionally thicker, straighter limb bones to keep the stress on each unit of bone manageable — exactly why an elephant’s legs look nothing like a scaled-up mouse’s.",[1255,195],"scaling laws",{"id":1257,"section":47,"level":95,"prompt":1258,"check":1259,"hints":1270,"solution":1272,"skills":1273},"human-body-anatomy.q076","How many neck (cervical) vertebrae does a giraffe have, compared with a human?",{"kind":56,"options":1260,"correct":1269},[1261,1263,1265,1267],{"id":59,"label":1262},"Far more than a human",{"id":62,"label":1264},"The same number, 7, just each one is much larger",{"id":65,"label":1266},"Far fewer than a human",{"id":68,"label":1268},"Giraffes have no neck vertebrae at all",[62],[1271],"The long neck comes from bone size, not bone count.","A giraffe has exactly 7 neck vertebrae, the same as a human. Its long neck comes from each bone being stretched enormously — not from having extra bones.",[1274],"animal comparisons",{"id":1276,"section":47,"level":95,"prompt":1277,"check":1278,"hints":1289,"solution":1291,"skills":1292},"human-body-anatomy.q077","Why is an octopus called an invertebrate?",{"kind":56,"options":1279,"correct":1288},[1280,1282,1284,1286],{"id":59,"label":1281},"It has no muscles at all",{"id":62,"label":1283},"It has no backbone or internal skeleton of any kind",{"id":65,"label":1285},"It lives only in the sea",{"id":68,"label":1287},"It has eight arms",[62],[1290],"Invertebrate literally means \"without a backbone\".","An octopus has no internal skeleton at all, only a small hard beak. \"Invertebrate\" means without a backbone; humans, giraffes and birds are vertebrates, built around one.",[1274],{"id":1294,"section":47,"level":145,"prompt":1295,"check":1296,"hints":1307,"solution":1309,"skills":1310},"human-body-anatomy.q078","What does Wolff’s law predict will happen to a limb kept unused in a cast for several months?",{"kind":56,"options":1297,"correct":1306},[1298,1300,1302,1304],{"id":59,"label":1299},"The bone will become denser",{"id":62,"label":1301},"Nothing will change at all",{"id":65,"label":1303},"The bone will lose density, because it is not being loaded",{"id":68,"label":1305},"The bone will change shape but not density",[65],[1308],"Bone responds to the load placed on it.","Wolff’s law states that bone adds material where it is loaded and loses it where it is not. A limb unused for months genuinely loses bone density, which is why rehabilitation afterwards focuses on carefully rebuilding load-bearing activity.",[1311,195],"bone remodelling",{"id":1313,"section":47,"level":178,"prompt":1314,"check":1315,"hints":1317,"solution":1319,"skills":1320},"human-body-anatomy.q079","A wheelbarrow has its wheel (fulcrum) 100 cm from the handles (effort) and the load 25 cm from the wheel. What is the mechanical advantage (effort arm ÷ load arm)?",{"kind":135,"answer":1316,"tolerance":201,"unit":759},4,[1318],"Divide the effort arm by the load arm.","Mechanical advantage = 100 ÷ 25 = **4**. Because this is greater than 1, the lever multiplies force: the load needs only a quarter of its own weight in effort to lift it — the opposite trade-off to the biceps’ third-class lever.",[1209,236],[1322,1323,1324,1325,1326,1327,1328,1329,1330,1331,1332,1333,1334],"human-body-anatomy-britannica-human-body","human-body-anatomy-britannica-skeleton","human-body-anatomy-britannica-muscle","human-body-anatomy-britannica-skin","human-body-anatomy-wikipedia-bone-list","human-body-anatomy-wikipedia-organ-list","human-body-anatomy-bianconi-cell-count","human-body-anatomy-wikipedia-anatomy-history","human-body-anatomy-wikipedia-medical-imaging","human-body-anatomy-wikipedia-cubit","human-body-anatomy-britannica-giraffe","human-body-anatomy-britannica-octopus","human-body-anatomy-ncert-textbooks","needs_review",{"generatedBy":1337,"notes":1338},"claude-code","Draft generated locally; pending owner review. Every numeric answer computed and asserted in scratchpad\u002Fhuman-body-anatomy\u002Ffacts.py.","0952587f8833e6f28debaecf5aacc0e5dd4319a4eeec24fb94da32780ff2699f",{"logic:questions":1341,"source:human-body-anatomy-bianconi-cell-count":1342,"source:human-body-anatomy-britannica-giraffe":1343,"source:human-body-anatomy-britannica-human-body":1344,"source:human-body-anatomy-britannica-muscle":1345,"source:human-body-anatomy-britannica-octopus":1346,"source:human-body-anatomy-britannica-skeleton":1347,"source:human-body-anatomy-britannica-skin":1348,"source:human-body-anatomy-ncert-textbooks":1349,"source:human-body-anatomy-wikipedia-anatomy-history":1350,"source:human-body-anatomy-wikipedia-bone-list":1351,"source:human-body-anatomy-wikipedia-cubit":1352,"source:human-body-anatomy-wikipedia-medical-imaging":1353,"source:human-body-anatomy-wikipedia-organ-list":1354},"e7fd7c240a65bea1bff6277f7af7cca65e2c7fcb13c6d756cb943d53f3cbc948","86a46797301346e8f555b991be692fef026b03adafcce61373363e59a5835b1d","fe734ecd8e1321840f0b057f6f381c193a4f158bb2b93230a8c97effe5146fd8","d8eb8accac4fca64e6711169db72028b260fb8b81c937c86516d9009896fa34c","b2397d7be01ef8cf5211da5eca1573ad62d46085f36d4db2ed08f21c53056557","ff731bc88cabecd2fcb3e598ad71f51239038521f29d0a83ebd4ce0c646c53ff","193bc0eb450e6145811c970ee092582c5438e4c1a9b77f43068da210057b43d4","2e0b8f545b04515ce65fc2b664b763d136911c4156af3a9d3b82fe3c668f5a95","efd8ff1189b2fa80028f5c70765a1028db96825546b54365d07ce2b79ce43928","2e38b5b54a6f8a770ee61851baef463aa46f63b175c4ef2bbb6cfb4c3145d147","12c5d62ebb8a2544cf16cbcbe8105c8a9cf1eccbc9b2131099e56d49e47bc134","83f6f8f69372660275a15f82235df3f7888a440fb9f356ffe9932c51afaa9bb4","98b8eb0ecb26f3bc5eb2865f6438bf36acda8025ce111d0ed0e3d4e5fb46f806","6ae52bf16d9cf93ff90c426eeb0f7cb7f36e504d5e893cbcecd97a44a5fb6c9e","preview-7e1cbbcc4f",1789899599786]