Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ d1a2a04

Topic 35 — The five vertebrate groups — the PP100's eight question types, with their nine exemplars

What this page is. James approves a bank's question TYPES before the bank is generated (vault: A bank is reviewed as its question types first, one exemplar each, 28 Sep 2026). This sheet writes the exemplars in full, exactly as they sit in content/G3T35.py (PP100, flagged TYPE_SHEET_ONLY). Eight types for six atoms; nine exemplars (type 2 is shown twice, once per atom, so every definition atom has an alone exemplar). No other bank item exists yet. Once the types stand, about fifty items are generated from them, varying the animal, the features' wording and the framing, easy-heavy.

What changed after the non-author review (29 Sep). The first draft's types 2 and 4 were one move ("which of these is true of every G", G varying) and are merged; the sheet is now eight types under the ceiling of ten, with two slots free — the reviewer would give one to the reptile atom, whose only alone-type is the named-animals recall (type 3). Type 1 takes James's praised Topic 1 form: every fact in the stem, the ask is which one sorts. Types 6 and 7's exemplars are fresh (a gannet and a fur seal; a ground-nesting bird) — the first draft's were a practice item and a quiz item with a noun changed. Type 5 is retagged easy (a one-step sort with both features in the stem). Two clang distractors are replaced by the real errors (the reptile confusion; the mouth).

The ceiling. Six atoms at two alone-types each would be twelve types; ten is the ceiling. The five definition atoms carry ONE alone-type each (types 1–4; type 2 covers two atoms) and the sort carries three (types 5, 7 and 8, with 8 the trap). Say if you want a second alone-type for the reptile atom in one of the two free slots.

James's rulings applied. Hard items are typed, never MCQs (28 Sep night): two text-entry types (the group's name from described features; the same against a misleading setting). Easy and medium are four-option MCQs. No stem leans on a video; no option bundles a verdict with a reason; every stem is a positive question; no exemplar is a lesson, quiz, attached or practice item with a noun changed (the inventory at the foot is the check); no headache character (Fabiola, Bertram, Ophelia, Evander, Gwendolen, Jonquil) appears in an item; no claim-maker appears on the sheet (a bare claim has two options; the bank's MCQs need four). Nothing James has rejected appears here.

How to read a type line. Each says what the stem asks, what the four options are (the kind of thing), and gives its exemplar scene. Every MCQ has a why (no per-option feedback in the bank; the engine prints Correct / Not quite). Tags follow depth of reasoning: easy = the deciding feature picked out of an animal's stated facts, the feature every member of a group has, the body part named, or a one-step sort with the features in the stem; medium = a named animal placed by remembered features, or two look-alikes told apart by one feature; hard = the group PRODUCED (typed) from features alone, or produced against a setting that pulls the other way.

The eight types

Hard because (type 7): the group is produced, not recognised — no name, no picture, no option list; the student holds the five rules and matches two features. Hard because (type 8): the sea and the swimming pull toward fish; the student must weigh two features (hair, milk) and one absence (it comes up to breathe, so no gills) against the setting, then produce the word. Medium because (type 3): the animals are named only, so the features are remembered and then matched. Medium because (type 6): two animals, two groups, one deciding feature picked from four statements true of both. Easy (type 5): one step, both features in the stem, four groups offered.

Bank notes for the generator. Type 1: every fact in the stem, the deciding one among three true non-deciders (where it lives, how it moves, what it eats, its size, its colour) — and in about half the bank's items one non-decider is a BODY feature that does not sort (a long tail, four legs, big eyes, a long nose), so the key is never simply "the body word" (cold read A); the animal varies across every group (which of these tells you the ostrich is a bird; the gecko a reptile; the newt an amphibian; the catfish a fish); never a fact that is false of the animal. Type 2: the group varies (every mammal; every reptile; every fish), and one distractor is always the popular belief (flies; four legs; scales; lives in water). Type 4: the fish varies; the options are always four body parts, the mouth always among them. Type 3: the key is a surprising member the lessons taught or a well-known one; the distractors are one animal from each of three other groups. Type 5: the four groups offered never omit the key's group; the animal is fresh and a little surprising (a porcupine's quills are hairs; an armadillo's shell; a flying fish). Type 6: FRESH pairs only, never a lesson's or a quiz's pair (a manatee and a grouper; a gharial and a sturgeon; a kingfisher and a water shrew; a sea snake is barred — see the egg rule); the four options are all true of both animals except the key. Types 7 and 8: the accept list is group_accept(word), generated; the stem never contains the group's word; type 8's setting always contradicts the group (a sea animal that is a mammal; a swimming animal that is a reptile; a flying animal that is a mammal), and its scenes are never the walrus, the sea lion, the seal or the otter (L05 q4, L01 q4, L02, L06 use them). PP-9 ⟂ L05 q4; PP-8 ⟂ PP-2 (draw one per test).

The egg-layers-only rule (review F02; binds every reptile the bank names). The reptile sentence says "lays its eggs on land", so the bank names ONLY reptiles that do: corn snake, king snake, python, cobra, tortoise, sea turtle, turtle, gecko, iguana, monitor lizard, bearded dragon, chameleon, anole, gila monster, crocodile, alligator. Never named as a reptile, in a stem or an option: rattlesnake, garter snake, boa, adder, skink, sea snake, slow-worm — they bear live young. The register note carries the same list (ATOM_PROPOSALS_G3T35.md, Note 3). Likewise no toad (its skin is bumpy and dry-ish) and no platypus or echidna (they lay eggs) anywhere in the bank.

Coverage (every atom alone, and the pairs)

Order in the file: easy PP-1…PP-5 → medium PP-6, PP-7 → hard PP-8, PP-9 (difficulty non-decreasing; S11 clean). Keys of the seven MCQs, in file order: PP-1 A · PP-2 B · PP-3 C · PP-4 D · PP-5 A · PP-6 B · PP-7 C (two A, two B, two C, one D — no letter over 30 %). Typed items: 2 of 9 on the sheet; in a bank of about fifty, types 7 and 8 supply 12–15 typed items on fresh feature lists.

Design-move inventory (every move on the page, then the bank's)

No bank exemplar shares a scene with a lesson, quiz, attached or practice item (the sloth, every bird, every amphibian, the perch, the porcupine, the python, the gannet and fur seal, the ground-nesting bird, the unnamed sea mammal appear nowhere else in the topic), and no two exemplars share a move except PP-2 / PP-3, which are one type shown on two atoms.

The exemplars, in full

Type 1 — PP-1 · LIF3-015 · easy

Stem: A sloth has fur, hangs from a branch, lives in the rainforest and moves slowly. Which of these tells you the sloth is a mammal?

• it has fur ← key
• it hangs from a branch
• it lives in the rainforest
• it moves slowly

Why: A mammal has hair or fur, and a mammal mother feeds her babies milk. / The sloth has fur. / So its fur tells you it is a mammal, not where it hangs or how it moves.

Type 2 — PP-2 · LIF3-016 · easy

Stem: Which of these is true of every bird?

• it builds a nest in a tree
• it has feathers ← key
• it can fly
• it has webbed feet

Why: A bird has feathers and a beak, and it lays eggs. / Every bird has feathers. / A penguin and an ostrich cannot fly, and not every bird nests in a tree or has webbed feet. / So feathers are true of every bird.

Type 2 — PP-3 · LIF3-018 · easy

Stem: Which of these is true of every amphibian?

• it has dry, scaly skin
• it lays its eggs on land
• it starts its life in water ← key
• it stays in water all its life

Why: An amphibian has smooth, moist skin. It starts its life in water, then lives on land. / Every amphibian starts its life in water. / Its skin is smooth and moist, its eggs are laid in the water, and it leaves the water for the land. / So starting its life in water is true of every amphibian.

Type 4 — PP-4 · LIF3-019 · easy

Stem: A perch lives in a lake. Which part of the perch takes in air from the water?

• its fins
• its tail
• its mouth
• its gills ← key

Why: A fish takes in air from the water with its gills. / Water flows in at the mouth, but the gills are the red combs that take in the air. / Its fins and tail are for swimming. / So the perch takes in air with its gills.

Type 5 — PP-5 · LIF3-012 + LIF3-015 · easy · drawing photo_porcupine_pp

Stem: This porcupine's quills are thick, stiff hairs, and a porcupine mother feeds her babies milk. Which group is the porcupine in?

• a mammal ← key
• a bird
• a reptile
• a fish

Why: Look at the features. / The porcupine's quills are hairs, and its mother feeds her babies milk. / Those are a mammal's features. / So the porcupine is a mammal.

Type 3 — PP-6 · LIF3-017 · medium

Stem: Which of these animals is a reptile?

• a heron
• a python ← key
• a salamander
• a goldfish

Why: A reptile has dry, scaly skin, and it lays its eggs on land. / A python has dry, scaly skin and lays its eggs on land. / A heron has feathers, a salamander has smooth, moist skin, and a goldfish has gills and fins. / So the python is the reptile.

Type 6 — PP-7 · LIF3-016 + LIF3-015 · medium

Stem: A gannet (a bird) and a fur seal (a mammal) both dive into the sea for fish. Which feature tells you the gannet is the bird?

• it dives for fish
• it lives by the sea
• it has feathers ← key
• it eats fish

Why: A bird has feathers and a beak, and it lays eggs. / The gannet has feathers; the fur seal has fur. / Both dive, both live by the sea and both eat fish, so those do not tell them apart. / So feathers tell you the gannet is the bird.

Type 7 — PP-8 · LIF3-012 + LIF3-016 · hard · text entry

Stem: An animal has feathers and a beak, and it lays its eggs in a nest in the tall grass. Type the name of its group.

Accept: group_accept("bird") — bird · a bird · birds · the bird · the birds · it is a bird · it's a bird (the grader folds case)

Why: Look at the features. / Feathers and a beak, and it lays eggs. / Those are a bird's features. / So the animal is a bird.

Hard because: no name, no picture, no option list — the group is produced from two features held against all five rules. ⟂ PP-2 (feathers as every bird's feature): draw one per test.

Type 8 — PP-9 · LIF3-012 + LIF3-015 against LIF3-019 · hard · text entry

Stem: An animal swims in the sea all its life, with flippers and a tail. It comes up to breathe air, it has a little hair, and its mother fed it milk. Type the name of its group.

Accept: group_accept("mammal") — mammal · a mammal · mammals · the mammal · the mammals · it is a mammal · it's a mammal

Why: Look at the features, not the sea. / The animal has hair, and its mother fed it milk. / It comes up to breathe air, so it has no gills. / Those are a mammal's features, so the animal is a mammal.

Hard because: the setting (the sea, swimming, flippers) pulls toward fish; two features and one absence must outweigh it, and then the word is typed. ⟂ L05 q4 (the walrus): the bank never puts the walrus, sea lion, seal or otter in this type.