Topic 27 · What a healthy ecosystem looks like, and what people do to it — the question types, for your rulings

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

Topic 27 — What a healthy ecosystem looks like, and what people do to it — 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 (51 items in content/G5T27_pp100_bank.py); this sheet is the way in. Each type line says what the stem asks, what the options are, and which atom it serves; one exemplar per type follows in full.

Rulings already applied. Four options on every MCQ (fixed sets: the three signs "many different kinds of living things / clean water / enough food for every eater" plus one tempting-wrong fourth per item (adjudication 8 Oct 2026: "short, tidy grass" read as absurd by both cold readers; now e.g. "only one kind of plant", "very clear water with nothing living in it"); the population set "It gets smaller. / It stays the same. / It grows. / It changes its body to fit the new place." — the fourth is SD-5's belief, a distractor only); no option bundles a verdict with its reason (the one claim is "Cora is wrong. What is the correct reason?" with four single-statement reasons); every item tagged to ONE atom; difficulty by depth of reasoning and rising with the atom's position (LIF5-020 12 easy, LIF5-022 13 hard); the hard tier recalls every coined term (habitat typed, harmful typed, beneficial and population by MCQ among their sisters — ten letters each, RECALL_BY_MCQ); every item a fresh instance (no lesson, quiz, attached, recall or practice scene; the belief's mowed lawn is the one noun shared, because the belief itself is tested); key letters A 10 · B 13 · C 17 · D 7 across 47 MCQs; key tells 0 of 104.

The bar list (things a generated item must never use): "predator" / "prey" (Topic 23 or 26 coins them); "species" (say "kind"); "non-living" (say "not alive"); "crashes", "collapses", "booms", "dies out" for a population (say "gets smaller", "leaves", "grows"); a population outside the chain keyed as changing; an animal that breaks the claim made about it (no tortoise, no non-US animal; a fish that lays eggs in gravel is a salmon or a trout, never a bass); a dam item on salmon (the Lesson 3 (Predict what a habitat change does to its populations) quiz's scene); any Austin stream, Trinity River or Everglades scene; "gravity", "leak", "lift", "snap"; a verdict joined to its reason in one option.

The ten types

Type	Items	Atom	Tags	Form	The stem asks…	The options / the accept	Exemplar scenes
1	8	020	easy	MCQ, the four-sign set	a described place: which sign of a healthy ecosystem it shows	many kinds / clean water / enough food / one tempting-wrong fourth	a Vermont lake with five kinds; a clear Idaho stream; a Louisiana marsh where cattails feed geese and geese feed foxes
2	4	020	easy → medium	MCQ, four places (one a drawn table)	which of four places is a healthy ecosystem / shows clean water / is the healthiest / shows the most signs (table)	four places	an Illinois pond against a ditch of algae, a parking lot, a mowed lawn; three Michigan lakes in a table
3	4	020	easy → medium	MCQ	what a dead log or a weed is in the ecosystem; which sentence about the log is true; what one kind of living thing means for the eaters	four single statements	a rotting Oregon log with beetles and mushrooms; Wisconsin pond weeds that snails eat; a Delaware pond of algae
4	1	020	medium	MCQ, the claim form	Cora's raked park is wrong. What is the correct reason?	four single-statement reasons	a raked New York park against the wild woods beside it (SD-3's belief)
5	6	021	easy → medium	MCQ	which of four actions is beneficial / harmful to a named ecosystem; why a named action is beneficial / harmful	four actions / four reasons	trash picked up on a Vermont stream bank; a pipe into an Alabama bay; a Georgia yard corner left to grow
6	9	021	medium	MCQ, the four-sign set	which sign the action brings back, keeps or takes away	many kinds / clean water / enough food / one tempting-wrong fourth	a stopped pipe in Illinois; willows on an Oregon bank; a mine's rusty water in Colorado; a marsh walkway in Ohio
7	4	020 / 021 / 022	hard	typed and MCQ	the coined word from its definition (habitat, harmful typed); the coined word among its sisters from a fresh case (beneficial; population)	habitat, harmful with child spellings / harmful, adapted, beneficial, extinct / a habitat, a food web, a population, an ecosystem	a factory yard in Oregon planted with grass and trees; all the trout in a Wyoming lake
8	8	022	medium → hard	MCQ, the population set (three with a drawn chain)	a habitat change and one named population: what happens to it (hard: two links chained, or a population outside the chain)	gets smaller / stays the same / grows / changes its body	a drained Indiana pond's pondweed, then its snails; a burned Colorado hillside's deer; Vermont swallows that ate dragonflies; Florida crows that never ate from the marsh
9	7	022	hard	MCQ, four populations (three with a drawn chain)	which population grows / gets smaller because it has less food / is first to grow / loses a named food; which sentence says why a population got smaller	four populations / four reasons	a drained Louisiana wetland; a Michigan marsh (cattails → geese → foxes); a cut Missouri woodland (acorns → mice → owls); a Massachusetts river mouth walled off; a drained Louisiana wetland (minnows, otters, water lilies, dry-ground grasses)
10	2	021 / 022	hard	multi-select	the TWO signs an action keeps; the TWO populations that get smaller because of who eats whom	the four-sign set / four populations on a drawn chain	an Arkansas tree strip between field and river; a Texas bay filling with mud (drawn chain seagrass → shrimp → redfish; the gulls at the dump sit outside it)

Hard because — type 7: the term is produced from its definition (typed) or recognised among sister words with the plain word absent. Type 8 hard: two links are chained (the dragonflies lose water, the swallows lose food), or the student must see that a population outside the chain is untouched. Type 9: two causes are told apart (losing water, losing food) and the chain is read for the right eater, or the order along the chain is reasoned. Type 10: a set answer traced along the chain, with the direct loser excluded.

⟂ draw constraints (never two on one test): PP-30 ⟂ PP-31 (the drained Indiana pond: PP-31 opens "Suppose the pondweed … has nearly all died, and the snails ate the pondweed", PP-30's answer — adjudication 8 Oct); PP-41 ⟂ PP-42 (the cut Missouri woodland: PP-42 opens "Suppose the mice … have become fewer", PP-41's answer — adjudication 8 Oct); PP-35 ⟂ the practice's typed habitat (two typed habitat definitions); PP-39 ⟂ PP-46 (the "which population grows" move on two land changes); PP-40 ⟂ PP-44 (the "less food, not less water" move on two chains); PP-17 ⟂ PP-10 (Cora's raked park and the Nebraska prairie field both carry the belief's mowed grass as a wrong option); PP-39 ⟂ PP-50 (two drained wetlands whose minnows get fewer — numbering corrected and the last pair added by the 8 Oct non-author review).

Design-move inventory, in brief (the move · the scene kind · the nearest lesson-side item): type 1 "name the sign a described place shows" · a lake, stream, marsh, valley, pond, bay · Lesson 1 (The signs of a healthy ecosystem), question 1–q3 (different places, the three-option set) · type 2 "pick the healthy place of four" · four land or water places in one state · Lesson 1 (The signs of a healthy ecosystem), question 9 (two ponds in a table; the bank's table has three lakes and four options) · type 3 "what the dead log or weed is; why one kind means little food" · a forest floor, a pond edge, an algae pond · Lesson 1 (The signs of a healthy ecosystem), question 5, q8 · type 4 "the belief's correct reason" · a raked park against wild woods · Lesson 1 (The signs of a healthy ecosystem), question 6 (Dev's golf course, bare yes / no) · type 5 "pick the beneficial or harmful action of four; the reason" · a stream bank, a bay, a prairie, a forest, a yard, a factory river · Lesson 2 (Beneficial or harmful: what people do to an ecosystem), question 1–q7 (two-option sorts) · type 6 "which sign the action touches" · a pipe stopped, willows planted, flowers cut, a marsh paved, rusty water, a walkway, campers' trash, clover · Lesson 2 (Beneficial or harmful: what people do to an ecosystem), question 8, q9 · type 7 "the term" · a definition stem; a factory yard restored; Wyoming trout · Lesson 1 (The signs of a healthy ecosystem), question 10, Lesson 2 (Beneficial or harmful: what people do to an ecosystem), question 10, Lesson 3 (Predict what a habitat change does to its populations), question 10, PR-12–15 · type 8 "one population's change" · a drained pond, a cleaned river, a burned hillside, a cut forest, a filled pond, a cleaned bay, a drained marsh with crows · Lesson 3 (Predict what a habitat change does to its populations), question 2–q6, the attached, PR-9, PR-10 · type 9 "which population" · a drained wetland, a drained marsh chain, a cut woodland chain, a walled river mouth, a cleaned stream, a plowed prairie, a drained Georgia marsh · Lesson 3 (Predict what a habitat change does to its populations), question 7–q9 · type 10 "the set" · a tree strip; a muddy bay chain · none on the lesson side.

One exemplar per type, in full

Type 1 (easy, LIF5-020). A lake in Vermont holds trout, frogs, water lilies, ducks and otters. Which sign of a healthy ecosystem does the lake show? — many different kinds of living things / clean water / enough food for every eater / no dead logs or weeds anywhere. Why: A healthy ecosystem has many different kinds of living things. The lake holds five different kinds. So the lake shows the sign many different kinds of living things.

Type 2 (easy, LIF5-020). Which of these four places in Illinois is a healthy ecosystem? — a ditch holding only green algae / a parking lot with one weed in a crack / a clear pond with twelve kinds of living things / a lawn mowed short, with one kind of grass. Why: A healthy ecosystem has many different kinds of living things and clean water. Only the pond has many kinds and clear water; the ditch, the parking lot and the lawn each hold one kind. So the pond is the healthy ecosystem.

Type 3 (easy, LIF5-020). A rotting log lies on a forest floor in Oregon, with beetles under its bark and mushrooms growing on top. Which sentence about the log is true? — The log should be taken away to keep the forest healthy. / The log shows that the forest is in poor health. / The log takes food away from the forest's living things. / The log is food and a home for the forest's living things. Why: Dead logs and weeds are part of a healthy ecosystem: they are food and homes. The beetles live under the log's bark, and the mushrooms feed on the log. So the log is part of a healthy ecosystem.

Type 4 (medium, LIF5-020, the one claim). Cora says a raked city park in New York, with every dead leaf and branch removed, is a healthier ecosystem than the wild woods beside it, but Cora is wrong. What is the correct reason? — The raked park has much cleaner water than the wild woods beside it have. / The wild woods hold far fewer kinds of living things than the raked park holds. / The wild woods hold many kinds of living things, fed by the dead leaves and branches. / The park's mowed grass makes much more food than the woods' trees make. Source: LIF5 register SD-3; Lesson 1 (The signs of a healthy ecosystem)'s lawn-and-meadow pair. Why: A healthy ecosystem has many different kinds of living things, and dead logs and weeds are part of it. The dead leaves and branches are food and homes, so the wild woods hold many kinds; the raked park holds few. So the wild woods are the healthier ecosystem, and Cora is not right.

Type 5 (easy, LIF5-021). Which of these four things is beneficial to the ecosystem of a stream in Vermont? — pouring used motor oil into the stream / picking up the trash along the bank / cutting down every tree along the bank / draining the stream to build a road. Why: What people do is beneficial when it keeps or brings back a sign of a healthy ecosystem. Picking up the trash keeps the water clean; the oil, the cutting and the draining each take a sign away. So picking up the trash is the beneficial thing.

Type 6 (medium, LIF5-021). A mine in Colorado lets rusty water run into a stream, and the stream turns orange. Which sign of a healthy ecosystem does the rusty water take away? — many different kinds of living things / clean water / enough food for every eater / soft mud on the bottom. Why: A healthy ecosystem has clean water. The rusty water turns the stream orange. So the rusty water takes away clean water.

Type 7 (hard, LIF5-021, typed). Trucks are driven across a marsh in Nebraska, and the marsh's many kinds of plants are crushed and gone. Type the one word we use for an action like this, one that takes away a sign of a healthy ecosystem. — accept harmful / harmfull / harm full / it is harmful / harmful to the ecosystem; wrong_fb for "bad", "beneficial", "harm", "damage", "pollute". Why: What people do is harmful when it takes away a sign of a healthy ecosystem. So the word is harmful.

Type 8 (hard, LIF5-022). A marsh in Florida is drained. Crows at a dump nearby eat trash, and never ate anything from the marsh. What happens to the crow population? — It gets smaller. / It stays the same. / It grows. / It changes its body to fit the new place. Why: When a habitat changes, a population that loses what it needs gets smaller, and the populations that ate it get smaller too. The crows needed nothing from the marsh and ate nothing from it. So the crow population stays the same.

Type 9 (hard, LIF5-022, drawn chain cattails → geese → foxes). A marsh in Michigan is drained, and the cattails need water. Which population is the first to get smaller because it has less FOOD? — the cattails / the geese / the foxes / the dry-ground grasses. Why: The populations that ate a population that got smaller get smaller too. The cattails get smaller because they lost water; the geese ate the cattails, so they are the first to lose food; the foxes lose food only after that. So the geese are the first to get smaller because they have less food.

Type 10 (hard, LIF5-022, multi-select, drawn chain seagrass → shrimp → redfish). A bay in Texas fills with mud from a building site, and the seagrass dies. Select the TWO populations that get smaller. — the gulls that eat trash at the dump / the shrimp / the redfish / the mice that live in the sand dunes. Why: The populations that ate a population that got smaller get smaller too. The shrimp ate the seagrass, and the redfish ate the shrimp; the gulls eat trash and the dune mice eat seeds, so neither loses food. So the shrimp and the redfish get smaller.