Topic 33 · Bones and muscles — the question types, for your rulings

Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ cca3af6

Topic 33 — Bones and muscles — the PP100's question types, with their exemplars

What this page is. James reads a bank as its question TYPES first (vault: A bank is reviewed as its question types first, one exemplar each). Under the Grade 5 standing brief the bank is built straight away (50 items in content/G5T33_pp100_bank.py); this sheet is the way in. Each type line says what the stem asks, what the four options (or the accept list) are, and prints one exemplar in full; beside each exemplar is its nearest lesson-side instance, so freshness can be checked in one look.

Rulings already applied. Four options on every MCQ (fixed sets: the parts "the skeleton / the heart / the lungs / the stomach"; the jobs "holding the body up / pumping blood round the body / taking in air / mashing up food"; the bones "the skull / the ribs / the backbone / the leg bones"; the soft parts "the brain / the heart and lungs / the stomach / the leg muscles"; the squeeze set "gets shorter and pulls / gets longer and pushes / gets shorter and pushes / gets longer and pulls"; the can-do set "pull only / push only / both / neither"; the four muscles "front of the upper arm / back of the upper arm / front of the thigh / back of the thigh"; the joint set; the two-muscles reasons). The key moves inside each set; the sets are declared to the key-tell checker (KEY_TELL_EXEMPT_SETS), which reports 0 of 95 MCQs flagged. Hard items are typed (five), a set (one multi-select) or ordered (one), plus four MCQs that chain two ideas or pick a reason; every hard item carries its "hard because" line. No claim item: the register's SD-6 names no belief about bones or muscles (its one belief, food and air down one tube, is Topic 31's), so no named child's claim is judged anywhere in the bank; the two "why" types pick the correct reason for a stated fact of the lesson. Difficulty rises with the atom's position (LIF5-061 eleven easy, four medium, two hard; LIF5-062 eight, five, three; LIF5-064 four, seven, six). Every item is tagged to exactly one atom. MCQ keys A 11 · B 11 · C 11 · D 10.

The bar list (real things and words a generated item must never use): "lift" (a bone is "pulled up"; the forearm "comes up"), "force", "energy", "gravity", "leak", "snap"; "tendon", "ligament", "biceps", "triceps", "hinge", "cartilage" (grades 6-8 or never); "push" as anything a muscle does (a distractor only); any lesson, quiz, attached, practice or intro scene (the rag doll, the bulging arm in class, the soup spoon, the monkey bars; the jellyfish, baseball, tackle, cat, tent, horse; the kangaroo, bucket, cat's jaw; the book shelf, frog, finger, pointed toes; the squirrel, goalkeeper, woodpecker, octopus, rower, swing, chicken wing, nodding head, bird, lizard, rabbit, elephant); a non-US animal (none used); an animal with no bones used as having a skeleton (an octopus, a jellyfish, an earthworm are the no-bones cases only).

The twenty-eight types

Type	Items	Atom	Tags	Form	The stem asks…	The options / the accept	Exemplar scene
1	2	061	easy	MCQ, the parts set / a plain set	which part holds the body (or a neck) up	the skeleton / the heart / the lungs / the stomach; the bones in its neck …	a gymnast on the beam; a giraffe's neck
2	2	061, 062	easy	MCQ, the jobs set	which job the skeleton does; what all the bones together are called; a muscle's job	the four jobs (fixed); skeleton / backbone / ribs / skull; the four jobs	a camel; a doctor's 200 bones; an eagle's wing
3	2	061	easy	MCQ, the bones set	which bone sits under a helmet / a seat belt	the skull / the ribs / the backbone / the leg bones	a hockey helmet; a seat belt
4	2	061	easy	MCQ, the soft-parts set	which soft part a named bone protected	the brain / the heart and lungs / the stomach / the leg muscles	a falling book; a climber's chest
5	3	061	easy	MCQ	what a boneless body does; which is a job of the skeleton; what gives a hamster its shape	four single statements	an earthworm; no scene; a hamster
6	3	062	easy	MCQ, the squeeze set / plain	what a squeezing muscle does; what a muscle that lets go does; what happens to a squeezing muscle's length	the 2 × 2 squeeze set; four single statements	a pitcher; a dancer; a boy
7	1	062	easy	MCQ, the can-do set	what a muscle can do to a bone	pull only / push only / both / neither	no scene
8	1	062	easy	MCQ	what the soft part that squeezes and shortens is	a muscle / a bone / a rib / a skull	a seal's flipper
9	1	062	easy	MCQ	what moves a monkey's bones	its muscles pulling on them / three wrong movers	a monkey
10	2	064	easy	MCQ / the joint set	what the place where two bones meet is called; what a joint is	a joint / …; the joint set (fixed)	a boy's arm; a goat's knee
11	2	064	easy, medium	MCQ	where bones move	at the joints / in the middle of each bone / …	a puppy; an owl's neck
12	2	064	easy, medium	MCQ	what the second muscle of a pair does; how many muscles a bend-and-straighten took	four single statements	no scene; a toddler's hug
13	2	061	medium	MCQ, the bones set	which bone protected the brain / the heart and lungs in a knock	the bones set	a hockey puck; a skateboard fall
14	4	061, 062	medium	MCQ on a drawing	the bone a "?" label points at; the part missing from a jobs table; the word on a blank PULLS chip	four bones; four parts; PUSHES / PULLS / RESTS / BENDS	the item skeleton; the jobs table; the straight arm
15	1	062	medium	MCQ	what the muscles are doing while nothing moves	They keep pulling on her bones. / three single statements	a gymnast hanging still
16	3	062	easy, medium	MCQ	what the muscles are doing to the bones while the body pushes a bar; what the muscles did to the bones in a leap; what long, thin muscles are doing	four single statements	a weightlifter; a cheetah; a sleeping raccoon
17	3	064	medium	MCQ, the four-muscles set	which muscle pulls for a named movement	the four muscles (fixed)	a climber; a heavy door; a skater's knees
18	1	064	medium	MCQ	why a leg bends at the knee	four single statements	a lamb
19	1	064	medium	MCQ	what the other muscle of the pair is doing	letting go / squeezing too / …	a girl's arm
20	1	061	hard	typed	the one word for all the bones together	skeleton, with article forms and child spellings	a whale
21	1	061	hard	typed	the bones that protect the heart and lungs	ribs, rib cage, with article forms	a dog's chest
22	1	062	hard	typed	the name of the soft part that squeezes and pulls	muscle, with article forms and child spellings	a frog's leg
23	1	062	hard	typed	the one thing a muscle can do to a bone	pull, pulls, pulling, pull on it …	no scene
24	1	062	hard	multi-select	the TWO things that happen when a muscle squeezes	gets shorter / gets longer / pulls on a bone / pushes on a bone	a sprinter
25	1	064	hard	typed	the name for a place where two bones meet	joint, joints, with article forms	a horse's leg
26	2	064	hard	MCQ, the reasons set	why a joint needs two muscles	the four single-statement reasons (fixed)	a kitten's knee; a robot arm that can push
27	1	064	hard	order	the steps of a bend-and-straighten, first to last	four steps	a boy answering the phone
28	2	064	hard	MCQ	what happens to a knee / an arm when the named muscles swap	four outcomes	a sitting boy; a diver

Hard because — types 20–23 and 25: the word is produced, not picked. Type 24: a set of two true statements held against their opposites. Type 26: the correct reason chains Lesson 2 (The muscles: they pull on bones, and they can only pull)'s no-push rule with Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint)'s pair (the robot item adds a contrast case that CAN push). Type 27: the whole movement ordered from the lesson's four steps. Type 28: two steps — which muscle is now pulling, then which way it moves the bone (and, for the diver, where the bones move).

One exemplar per type, in full

Type 1 (easy, LIF5-061). A gymnast stands up straight on the beam. Which part of her body holds her up? — the skeleton / the heart / the lungs / the stomach. Why: All the bones of the body together are called the skeleton. The skeleton holds the body up. So her skeleton holds her up. (nearest lesson-side instance: Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside), question 1, the girl at the bus stop)

Type 2 (easy, LIF5-061). A camel's skeleton is all its bones together. Which job does the skeleton do? — pumping blood round the body / taking in air / mashing up food / holding the body up. Why: The skeleton holds the body up, gives it its shape, and protects the soft parts inside. Pumping blood is the heart's job, taking in air is the lungs' job, and mashing food is the stomach's. So the skeleton's job is holding the body up. (no lesson-side twin: the jobs set is the bank's; Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside)'s quiz asks what holds a body up)

Type 3 (easy, LIF5-061). A hockey player's helmet sits over the bone round his brain. Which bone is that? — the backbone / the leg bones / the skull / the ribs. Why: The skull is the hard case of bone round the brain. So the bone under his helmet is the skull. (nearest: Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside), question 6, the bike helmet, which asks the soft part instead)

Type 4 (easy, LIF5-061). A heavy book falls off a shelf onto a girl's head, and she is fine. Which soft part did her skull protect? — the heart and lungs / the stomach / the leg muscles / the brain. Why: The skull protects the brain. So the soft part the skull protected is the brain. (nearest: Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside), question 4, the baseball, which asks the bone)

Type 5 (easy, LIF5-061). An earthworm has no bones inside it. What does its body do when it is out of the soil? — It stands up stiff and straight. / It stays soft and flops. / It keeps the shape of a box. / It becomes hard like a stick. Why: The skeleton holds the body up and gives it its shape. An earthworm has no bones inside it. So nothing holds its body up or stiff, and it stays soft and flops. (nearest: Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside), question 2, the jellyfish on the sand, two options)

Type 6 (easy, LIF5-062). A pitcher's arm muscle squeezes as she throws. What does the muscle do? — It gets shorter and pulls on the bone. / It gets longer and pushes on the bone. / It gets shorter and pushes on the bone. / It gets longer and pulls on the bone. Why: When a muscle squeezes, it gets shorter and pulls on the bone it is fixed to. So the pitcher's muscle gets shorter and pulls on the bone. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 2 and q3, length and pull asked separately)

Type 7 (easy, LIF5-062). Which of these can a muscle do to a bone? — push only / both pull and push / neither pull nor push / pull only. Why: A muscle can pull, but it can never push. So a muscle can pull a bone only. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 8, the bird's wing, three options)

Type 8 (easy, LIF5-062). A seal's flipper bends when a soft part inside it squeezes and gets shorter. What is that soft part? — a bone / a muscle / a rib / a skull. Why: A soft part that squeezes and pulls on bones is called a muscle. The part in the flipper is soft, and it squeezes and gets shorter. So it is a muscle. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 1, the thigh)

Type 9 (easy, LIF5-062). A monkey swings through the trees. What moves the monkey's bones? — its skin stretching over them / its bones pushing each other / its muscles pulling on them / the air pushing on them. Why: Muscles pull on bones to move the body. The monkey's muscles squeeze and pull on its bones. So its muscles pulling on them move the bones. (no lesson-side twin: the quiz never asks "what moves the bones" as a whole)

Type 10 (easy, LIF5-064). A boy's arm bends at his elbow. What is the place where two bones meet called? — a joint / a muscle / a rib / a skull. Why: A joint is also the place where two bones meet. So the place where two bones meet is a joint. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint), question 2, the dog's back leg)

Type 11 (easy, LIF5-064). A puppy's leg bones move when it runs. Where do bones move? — in the middle of each bone / at the joints / under the skin only / at the ribs. Why: Bones move at the joints. So the puppy's leg bones move at its joints. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint), question 6, the frog)

Type 12 (easy, LIF5-064). Muscles at a joint work in pairs. What does the second muscle of a pair do? — It pushes the bone back. / It pulls the bone the same way. / It pulls the bone back. / It holds the two bones apart. Why: Muscles work in pairs: one muscle pulls the bone one way, and the other muscle pulls the bone back. So the second muscle pulls the bone back. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint), question 7, the finger, which asks how many muscles)

Type 13 (medium, LIF5-061). A hockey puck hits a player on the side of the head, and her brain is not hurt. Which bone protected her brain? — the skull / the ribs / the backbone / the leg bones. Why: The skull is the hard case of bone round the brain, and it protects the brain. The puck hit her head. So her skull protected her brain. (nearest: Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside), question 4, the baseball)

Type 14 (medium, LIF5-062). [the straight arm with a blank chip on the short, fat muscle on the back] Here is a drawing of a straight arm, with a chip on one muscle left blank. Which word belongs on the chip? — PUSHES / PULLS / RESTS / BENDS. Why: When a muscle squeezes, it gets shorter and fatter and pulls on the bone it is fixed to. The muscle with the blank chip is short and fat, so it is squeezing. So the word on the chip is PULLS. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 10, the bent arm with the blank chip on the front muscle)

Type 15 (medium, LIF5-062). A gymnast hangs from a bar with her arms bent and quite still. What are the muscles in her arms doing? — They pull on nothing. / They keep pulling on her bones. / They push on her bones. / They go long and thin. Why: When a muscle squeezes, it pulls on the bone it is fixed to. Her arms stay bent only while the muscles keep squeezing. So yes, the muscles keep pulling on her bones, even though nothing moves. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 7, the bucket held still, bare yes / no)

Type 16 (medium, LIF5-062). A cheetah's leg muscles squeeze, and the cheetah leaps forward. What did the muscles do to its leg bones? — They pushed the bones. / They let the bones go. / They pulled the bones. / They made the bones longer. Why: Muscles pull on bones to move the body. The cheetah's leg muscles squeezed and got shorter. So they pulled its leg bones, and the cheetah leaped. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 6, the kangaroo)

Type 17 (medium, LIF5-064). A climber pulls herself up, bending her arms at the elbows. Which muscle pulls each forearm up? — the muscle on the front of the upper arm / the muscle on the back of the upper arm / the muscle on the front of the thigh / the muscle on the back of the thigh. Why: Muscles work in pairs: one pulls the bone one way, and the other pulls it back. The muscle on the front of the upper arm pulls the forearm up, and the arm bends. So the muscle on the front of the upper arm is pulling. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint)-V1, the boy bending his arm, two options)

Type 18 (medium, LIF5-064). A lamb's leg bends at its knee but not along its thigh bone. Why does the leg bend there? — The knee is a joint, where two bones meet. / The knee has the thickest muscle. / The thigh bone is softer at the knee. / The skin is loosest at the knee. Why: Bones move at the joints, the places where two bones meet. At the knee, the thigh bone meets the lower-leg bones. So the leg bends at the knee and not along the thigh bone. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint), question 3, the runner)

Type 19 (medium, LIF5-064). The muscle on the back of a girl's upper arm squeezes, and her arm straightens. What is the muscle on the front doing? — squeezing too / letting go / pushing the forearm down / pulling the forearm down. Why: Muscles work in pairs, and when one muscle squeezes, the other lets go. The muscle on the back is squeezing. So the muscle on the front is letting go. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint), question 4, the boy's arm bending, asked the other way round)

Type 20 (hard, LIF5-061, typed). A whale has more than 150 bones, and together they hold up its huge body and give it its shape. Type the one word for all the bones of a body together. — accept: skeleton, the skeleton, a skeleton, its / his / her skeleton, skeletons, skeliton, skeletan, skelaton, skeleten, skelton, skelleton. Why: All the bones of the body together are called the skeleton. So the one word is skeleton. (nearest: Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside), question 11, the horse; PR-13, the lizard)

Type 21 (hard, LIF5-061, typed). A cage of long, curved bones round a dog's chest protects its heart and lungs. Type the name of those bones. — accept: ribs, the ribs, its / his / her ribs, rib, the rib, rib bones, the rib bones, ribcage, rib cage, the rib cage, ribbs. Why: The ribs are a cage of long, curved bones round the heart and lungs, and they protect them. So the bones are the ribs. (nearest: Lesson 1 (The skeleton: bones that hold you up and protect the soft parts inside), question 7, the man's ribs, by MCQ the other way round)

Type 22 (hard, LIF5-062, typed). In a frog's back leg, a soft part fixed to two bones squeezes, gets shorter, and pulls on the bones. Type the name of this kind of part. — accept: muscle, a muscle, the muscle, muscles, mussel, musle, mucle, muscel, musel, mussle, muscule. Why: A soft part that squeezes and pulls on bones is called a muscle. So the part is a muscle. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 11, the runner's leg; PR-15, the elephant's trunk)

Type 23 (hard, LIF5-062, typed). A muscle can do one thing to a bone, and it can never do the opposite. Type the one thing a muscle can do to a bone. — accept: pull, pulls, pulling, a pull, it pulls, pull it, pull on it, pull the bone, pulls the bone, pull on the bone, pulls on the bone, pulled, to pull. Why: A muscle can pull, but it can never push. So the one thing a muscle can do to a bone is pull. (nearest: Lesson 2 (The muscles: they pull on bones, and they can only pull), question 8, the bird's wing, by MCQ)

Type 24 (hard, LIF5-062, multi-select). A sprinter's leg muscle squeezes. Select the TWO things that happen. — The muscle gets shorter. / The muscle gets longer. / The muscle pulls on a bone. / The muscle pushes on a bone. Why: When a muscle squeezes, it gets shorter and pulls on the bone it is fixed to. A muscle can pull, but it can never push. So the two things that happen are: the muscle gets shorter, and the muscle pulls on a bone. (nearest: PR-6, the horse's leg muscle, as one four-way MCQ)

Type 25 (hard, LIF5-064, typed). A horse's front leg bends at a place where two bones meet. Type the name for a place where two bones meet. — accept: joint, a joint, the joint, joints, joynt, joint bone, a joint bone. Why: A joint is also the place where two bones meet. So the name is joint. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint), question 2, the dog's back leg, by MCQ)

Type 26 (hard, LIF5-064). Two muscles are fixed across a kitten's knee, one on the front and one on the back. Why does the knee need two muscles? — A muscle gets tired, so a second muscle takes a turn. / A bone is heavy, so two muscles are needed to push it. / A joint comes apart unless two muscles hold it. / A muscle can only pull, so a second muscle pulls the bone back. Why: A muscle can pull, but it can never push. Muscles work in pairs: one pulls the bone one way, and the other pulls it back. So the knee needs a second muscle to pull the bone back. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint), question 5, the upper-arm muscle that cannot straighten the arm; PR-9, the elbow)

Type 27 (hard, LIF5-064, order). A boy bends his arm to answer the phone, then straightens it. Tap the steps in the order they happen, first to last. — The muscle on the front of his upper arm squeezes and gets shorter. → The muscle on the front pulls the forearm bones up, and the arm bends at the elbow joint. → The muscle on the front lets go, and the muscle on the back squeezes. → The muscle on the back pulls the forearm bones down, and the arm straightens. Why: A squeezing muscle pulls on its bone, and bones move at the joints. Muscles work in pairs: one pulls the bone one way, and the other pulls it back. So the front muscle squeezes and pulls the forearm up; then the back muscle squeezes and pulls it down. (nearest: Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint)'s FRQ, the dancer's ankle, written out)

Type 28 (hard, LIF5-064). A boy sits with his knee bent. Then the muscle on the back of his thigh lets go, and the muscle on the front of his thigh squeezes. What happens to his knee? — It bends more. / It straightens. / It stays bent. / It bends the other way. Why: The muscle on the front of the thigh pulls the lower leg forward, and the knee straightens. The front muscle is squeezing and the back one has let go. So his knee straightens. (nearest: PR-8, the girl on the swing, which names the movement and asks the muscle)

Draw constraints (⟂: never on one test together)

• PP-7 (which job of the skeleton: protecting) ⟂ PP-2 (which job: holding up) — one states the other's distractor as its key; harmless as a pair of facts, but two from the jobs set in one test is one item twice.
• PP-13 (pull only) ⟂ PP-19 (the weightlifter: pulling on them) ⟂ PP-43 (typed pull) ⟂ PP-44 (multi: shorter and pulls): PP-19's key and PP-44's key print the typed answer; draw one of the four.
• PP-20 (a joint) ⟂ PP-22 (what is a joint) ⟂ PP-45 (typed joint): each option set prints another's key.
• PP-46 ⟂ PP-50 (the same reasons set, both keyed on the same reason).
• PP-39 (two muscles, one each way) ⟂ PP-46 / PP-50 (the reasons set says why two).
• PP-26 (the "?" skull) ⟂ PP-3 (the skull under a helmet) — the bones set lists the answer.
• Adjudication, 8 Oct 2026 (bundle ids): PP-13 (pull only) ⟂ PP-43 (typed pull); PP-18 (the job of a muscle: pulling on bones) ⟂ PP-43; PP-02 (the skeleton's job, "A camel's skeleton is all its bones together") ⟂ PP-09 (what all the bones are called) and PP-40 (typed skeleton); PP-20 and PP-22 (a joint, the joint set) ⟂ PP-45 (typed joint); PP-46 (the kitten: its own four reasons) ⟂ PP-50 (the robot arm: the reasons set) — both keyed on the no-push rule.

Order convention

Type 27's key is stored first to last, the direction the stem asks (items in the authored order); no sibling item asks the reverse.

Review pass, 8 Oct 2026 (non-author): PP-19 re-asked (the can-do verdict-and-reason bundles became "what are the muscles doing to his arm bones" while he pushes a bar; type 7 → 16); PP-20's stem no longer says an arm bends "only at one place"; PP-28, the raccoon and the toddler items carry single-statement options (no "yes, …", no ", so …", no count-plus-reason); the owl's fourth option is "nowhere in the neck"; the order item's second step names the muscle; the typed PULL accept list gained the forms a child writes ("pull on bones", "it can pull", "pull it up"). Type counts and the exemplars above are updated in place.

Adjudication fix pass, 8 Oct 2026: PP-15's key reads "It does not pull the bone." and PP-28's distractor "They are letting go." (the two no longer share a phrase); PP-35 (the skater's knees) and PP-48 (the sitting boy's knee) are re-scened to the arm (a push-up; a ball held at the shoulder) because the Lesson 3 (How the skeleton and muscles work together: a pair of muscles at a joint) video shows only the arm pair — the knee pair is article-only, so a video-only child would be trapped by "front bends"; PP-46 left the reasons set for four single-statement reasons of its own; PP-18's stem no longer says "pull"; the whale's typed item steers "skeleton bones" to the one word. No key letter moved.