Topic 23 · What an ecosystem is — the question types, for your rulings

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

Topic 23 — What an ecosystem is — 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 (59 items in content/G5T23_pp100_bank.py); this sheet is the way in. Each type line says what the stem asks and what the options (or the accept list) are, and prints one exemplar in full. Tags follow depth of reasoning — easy = a one-step pick (which sentence is true of an ecosystem; which of four parts is abiotic; what does it depend on X for; how do they affect each other); medium = the rule applied with a second step (the once-alive boundary; the living thing picked out of the things it also uses; a reason picked; predator or prey named); hard = a set answer, a word produced, two pairs classified and matched, the boundary of "predator" judged among four eaters, a documented belief judged by its reason — and rise with the atom's order: LIF5-001 seven easy, one medium, two hard; LIF5-002 six easy, four medium, one hard; LIF5-003 three easy, five medium, two hard; LIF5-005 three easy, four medium, two hard; LIF5-004 (the capstone) six easy, six medium, seven hard. Every hard item carries a one-line "hard because" (hb) in the bank file.

Rulings already applied. Four options on every MCQ (fixed sets: FOR4 food / a place to live or hide / both / nothing; NOTALIVE4 water / air / sunlight / soil; WAYS4 one eats the other / both need the same food / each helps the other / they do not affect each other; the key moves); no option bundles a verdict with its reason (the ONE bank claim is "Willa is wrong. What is the correct reason?" with four single-statement reasons; no tier-2 exception used); every stem is a positive question of at most two sentences unless tagged hard; the beach list card's blind text lists the seven parts as data, never the count; "ecosystem", "biotic" and "abiotic" are recalled by MCQ (RECALL_BY_MCQ); the typed keys are "predator", "prey" and "water" (one word each, child spellings in the accept lists); three multi-selects, where the answer is genuinely a set; every item names ONE atom; US spelling; units as words. MCQ keys A 17 · B 14 · C 14 · D 6. KEY TELLS: 0 of 127 MCQs flagged.

The bar list (things a generated item must never use): "non-living" (say "not alive" / "never alive"); the grades 6-8 names competition / mutualism / parasitism; "one lives on the other" as a fourth way; a predator that eats a plant; "gravity", "leak", "lift", "snap"; any lesson scene (the pond and its frogs, fish, cattails, lily pads, dragonflies, mud, heron, turtle, blackbird; the meadow and its hawk, mouse, owl, bee, clover, rabbit, deer; the oak forest in Georgia); any quiz, attached, summary, practice or recall-bank scene (the stream with trout and willows, the coral reef, the truck, the desert with cactus, lizards and owls, the prairie dogs, the pine forest rain, the kite over the beach; the mushroom on a log, the dead branch, rain water in a dip, the blue jay feather, the wind, the pine cone, the beach list; the woodpecker in a dead tree, the monarch and the milkweed, the clownfish, the hummingbird and the trumpet flower, the hermit crab, the bald eagle and the pine, the honeybee, the beavers and the aspens; the earthworm, the whale, the sunflower, the trout in a stream, the salamander, the gliding hawk, the desert tortoise, the sea otter and the kelp; the sea otter and the crab, the hummingbird and the red flower, the coyotes and bobcats, the robins, the caterpillar and the cabbage, the cleaner shrimp, the barn owl and the rat, the shark and the seal, the goat, the bobcat and the turkey; the squirrel and the oak, the lizard on a rock, the fox and the rabbit, the river with willows, the fallen leaf, the wolf and the deer; the aloe, the backyard web, the salt marsh, the mountain stream pebble, the backyard hose and dandelion, the barnacle and the whale, the beavers under ice, the badger and the gopher, the two kinds of woodpecker, the mountain lion and the bighorn sheep; the cloud, the guinea pig, the goldfish, the salamander under a log, the fern, the stream web); a claim-maker other than Willa (Wesley voices the belief in Lesson 1 (What an ecosystem is: living things and the things they use, together); Victor is the headache character and never appears in an item); a non-US animal or place; "biggest / smallest" for an amount.

The ten types

Type	Items	Atom	Tags	Form	The stem asks…	The options / the accept	Exemplar scenes
1	3	001	easy → hard	MCQ	which sentence about a place's ecosystem is true; why a thing not alive belongs; Willa's claim: the correct reason (hard)	four sentences in one frame / four reasons	a Florida swamp; a marsh; Willa's swamp
2	5	001	easy, one hard multi	MCQ, one multi	which of four things belongs to the place's ecosystem (three are not alive and not used, or living and far away); the TWO things not alive that belong (multi, hard)	four things	a kelp forest; a tide pool; a Kentucky cave; a Kansas prairie; a Maine shore
3	2	001	easy	MCQ	what all of a place's living things and the things they use are called; which of four is an ecosystem	ecosystem / food chain / food web / life cycle; four scenes	salmon, bears and spruce in Alaska; a marsh among a flock, a box of shells and a drawing
4	7	002	easy, one hard multi	MCQ, one multi	which of four parts of a place is abiotic (or biotic); the TWO abiotic parts (multi, hard)	four parts of one place	a swamp; a mountain valley; a seashore; a river; a city park; a garden; a small river
5	4	002	medium	MCQ	the once-alive boundary: which word describes a dead log; which is biotic though not alive now; why a pine needle is biotic; which pair is one biotic and one abiotic	biotic / abiotic / ecosystem / predator; four things; four reasons; four pairs	a fallen log; a dead crab; a pine needle; a rattlesnake and a sand dune
6	4	003	easy → medium	MCQ, the FOR4 set	a described pair: what does X depend on Y for	food / a place to live or hide / both / nothing	a manatee and sea grass; a chickadee and a maple; a bluebird and a dead tree; a quail and a bush
7	6	003	medium → hard	MCQ	which living thing does X depend on for food; which sentence is true of a hunt; which sentence says how X depends on another LIVING thing; the one living thing among four things used (hard); depending only for a place to hide (hard)	four living things / four sentences / four things	an armadillo; a salmon and a grizzly; a chipmunk; a cowbird on a bison; a kingfisher; a young trout under roots
8	9	005	easy → hard	MCQ, the NOTALIVE4 set; sentences; one typed	which thing not alive does X depend on; which sentence says how X depends on a thing not alive; which living thing loses the thing it breathed (hard); the one word for what a fish takes oxygen from (typed, hard)	water / air / sunlight / soil; four sentences; four living things; water with child spellings	a desert tortoise; a dolphin; duckweed; a clam; a snake on a warm road; moss; mountain goats; a shrinking lake; a bass
9	11	004	easy → hard	MCQ, the WAYS4 set; one multi	a described pair: how do they affect each other; which pair both need the same food; why two bluebirds affect each other; the pair that affects each other the SAME way as a given pair (hard); the TWO pairs where one eats the other (multi, hard)	one eats the other / both need the same food / each helps the other / they do not affect each other; four pairs; four reasons	a bear and a salmon; bison and pronghorn; ants and aphids; a ladybug; a butterfly and an apple tree; seals and sea lions; gulls and clams; a tick and a dog; loons and ospreys
10	8	004	medium → hard	MCQ then typed	which animal is the predator / the prey; which pair of words fits; which of four eaters is a predator (hard: the plant-eater boundary); the term produced (typed, hard)	the first animal / the second / both / neither; predator and prey / prey and predator / two predators / two prey; predator or prey with child spellings	a bat and a moth; a pelican; a garter snake and a slug; a toad among grass-eaters; a coyote; a shark; a lynx

Hard because — type 1: a documented belief (the register's SD-1) judged by its correct reason among three wrong reasons. Type 2 and 4 multis: a set of two picked by two tests each. Type 7: two sorts at once (living or not alive, then food or a place), or one living thing picked from four things used. Type 8: two steps (which thing not alive is lost, then who breathed it), or the word produced. Type 9: two pairs classified and matched; a set of two pairs. Type 10: the boundary of "predator" judged among four eaters; the term produced from a described hunt.

⟂ draw constraints (never two on one test): PP-55 ⟂ PP-56 ⟂ PP-57 ⟂ PP-58 (the four typed predator / prey items: at most two per test, and never both coyote items, 55 and 56); adjudication 8 Oct 2026: each of PP-55 to PP-58 ⟂ PP-40, PP-41, PP-42 and PP-52 (an MCQ printing "predator" / "prey" never sits on a test with a typed item asking for the word); PP-27 ⟂ PP-28 ⟂ PP-29 (the three once-alive items: one's stem or why states the rule the next one tests); PP-47 (the small-river multi) ⟂ PP-11 (the river biotic item); PP-21 (bison and pronghorn) ⟂ PP-35 (the cowbird on the bison); PP-25 (seals and sea lions) ⟂ PP-57 (the sea-lion prey typed item); PP-1 (the swamp sentence) ⟂ PP-8 (the swamp mud) ⟂ PP-59 (Willa's swamp); PP-20 (the bear and the salmon) ⟂ PP-32 (the salmon and the grizzly); PP-27 (the fallen log) ⟂ PP-29 (the pine needle); PP-43 (two gulls and clams) ⟂ PP-44 (two bluebirds); PP-22 (ants guard aphids) ⟂ PP-23 (a ladybug eats aphids); PP-40 (the bat) ⟂ PP-41 (the pelican) ⟂ PP-42 (the garter snake).

One exemplar per type, in full

Type 1 (easy, LIF5-001). A swamp in Florida holds alligators, egrets and cypress trees, with warm water, mud and sunlight. Which sentence about the swamp's ecosystem is true? — It is the alligators and the egrets, and nothing else in the swamp. / It is the warm water, the mud and the sunlight, and nothing else. / It is the living things and the things that are not alive that they use, together. / It is the cypress trees and the mud they grow in, and nothing else. Why: The alligators, the egrets and the cypress trees are the swamp's living things. The water, the mud and the sunlight are not alive, but the living things use them. All of them, together, are the swamp's ecosystem. (nearest lesson-side instance: Lesson 1 (What an ecosystem is: living things and the things they use, together), question 1 and q4, the stream and the desert lists — there the lists, here the sentences)

Type 2 (easy, LIF5-001). A kelp forest grows in the sea off the coast of California, with sea otters, fish and sea urchins. Which of these also belongs to the kelp forest's ecosystem? — the cold salt water the kelp grows in / a ship sailing far out at sea / a gull's nest on a cliff miles away / a surfboard left on the beach. Why: An ecosystem is the living things in a place, together with the things that are not alive that they use. The kelp, the otters, the fish and the urchins all live in the cold salt water. So the salt water belongs to the kelp forest's ecosystem. (nearest: Lesson 1 (What an ecosystem is: living things and the things they use, together), question 3 and q7, the truck and the kite — the not-used near misses, there as yes / no)

Type 3 (easy, LIF5-001). Salmon, bears and spruce trees live along a river in Alaska, with its cold water, gravel and sunlight. What do we call all of them, together? — a food chain / a food web / an ecosystem / a life cycle. Why: All the living things in a place, together with the things that are not alive that they use, are called an ecosystem. The salmon, the bears and the spruce trees are the living things, and the water, the gravel and the sunlight are the things they use. So all of them, together, are an ecosystem. (nearest: Lesson 1 (What an ecosystem is: living things and the things they use, together), question 9, the term recognised among its sisters)

Type 4 (easy, LIF5-002). Which of these four parts of a mountain valley is biotic? — a boulder / the snow / a wildflower / the wind. Why: A part that is alive, or was once alive, is biotic. The boulder, the snow and the wind were never alive. The wildflower is alive, so the wildflower is biotic. (nearest: Lesson 2 (Biotic or abiotic: sorting the parts of an ecosystem), question 1 to q7, one part each as biotic / abiotic — here four parts, one keyed)

Type 5 (medium, LIF5-002). Why is a fallen pine needle on the forest floor biotic? — It was once part of a living tree. / It is lying on the soil. / It is brown and dry. / It will rot away one day. Why: A part of an ecosystem that is alive, or was once alive, is biotic. The pine needle grew on a living pine tree. So the pine needle is biotic because it was once part of a living tree. (nearest: Lesson 2 (Biotic or abiotic: sorting the parts of an ecosystem), question 2, q5 and q7, the dead branch, the feather and the pine cone — the verdict there, the reason here)

Type 6 (easy, LIF5-003). A bluebird catches beetles on the bark of a dead tree and nests in a hole in the same tree. What does the bluebird depend on the dead tree for? — food / a place to live or hide / both food and a place to live or hide / nothing: it does not depend on it. Why: The bluebird eats the beetles on the tree's bark: food. It nests in a hole in the tree: a place to live. So the bluebird depends on the dead tree for both. (nearest: Lesson 3 (How a living thing depends on other living things), question 1, the woodpecker in a dead tree — the same move on a different bird and a fourth option)

Type 7 (hard, LIF5-003). A kingfisher eats small fish, and it digs its nest tunnel into a sandy river bank. Which of these is a LIVING thing the kingfisher depends on? — the river bank / the small fish / the river water / the sand. Why: The river bank, the water and the sand were never alive. The small fish are alive, and the kingfisher eats them. So the small fish are the living thing the kingfisher depends on. Hard because: the one living thing picked out of four things the bird uses, three of them not alive. (nearest: Lesson 3 (How a living thing depends on other living things), question 6, the bald eagle's pine and fish — both living there)

Type 8 (hard, LIF5-005, typed). A bass swims in a lake and takes in oxygen through its gills. Type the one word for the thing that is not alive that it takes the oxygen from. — accept water / the water / lake water / watter…; wrong_fb for air, oxygen, gills, lake. Why: A fish needs air too: it takes in oxygen from the water through its gills. The bass is a fish in the lake. The one word is water. (nearest: Lesson 4 (How a living thing depends on things that are not alive), question 4, the trout in a stream — picked from the set there, produced here)

Type 9 (hard, LIF5-004). On a lake, loons and ospreys both catch and eat the same fish. Which other pair affects each other in the SAME way as the loons and the ospreys? — two raccoons that both eat the crayfish in one small river / a raccoon that catches and eats a crayfish in a river / a crayfish that hides under a stone in a river / a stone that the river's water rolls along the bottom. Why: The loons and the ospreys both need the same food. Two raccoons that both eat the crayfish in one river also both need the same food. So the two raccoons are the pair that affects each other in the same way. Hard because: two pairs classified, the given one's way found and the matching pair picked. (nearest: Lesson 5 (How two living things affect each other), question 3 and q4, the coyotes and bobcats, the two robins — one pair each there)

Type 10 (hard, LIF5-004). Which of these animals is a predator? — a grasshopper that eats grass / a bison that eats grass / a toad that catches and eats grasshoppers / a cow that eats hay. Why: A predator is an animal that hunts and eats another animal. The grasshopper, the bison and the cow eat plants, so none of them is called a predator. The toad catches and eats grasshoppers, which are animals, so the toad is a predator. Hard because: the boundary of the word judged among four eaters — eating a plant is not being a predator. (nearest: Lesson 5 (How two living things affect each other), question 9, the goat and the grass — yes / no there)

The design-move inventory (one line per item: the move, the scene kind, the nearest earlier item)

#	d	Atom	Move	Scene kind	Nearest earlier
1	easy	001	pick the true sentence about a place's ecosystem	a Florida swamp	Lesson 1 (What an ecosystem is: living things and the things they use, together), question 1 / q4 (lists)
2–4, 7	easy	001	pick the one thing not alive that the place's living things use	a kelp forest; an Oregon tide pool; a Kentucky cave; a Kansas prairie	Lesson 1 (What an ecosystem is: living things and the things they use, together), question 2, q5, q6 (yes / no)
5–6	easy	001	name the whole; pick the one scene that is an ecosystem	an Alaska river; a marsh among three non-places	Lesson 1 (What an ecosystem is: living things and the things they use, together), question 9
8–13	easy	002	which of four parts is abiotic / biotic	a swamp; a mountain valley; a seashore; a river; a city park; a garden	Lesson 2 (Biotic or abiotic: sorting the parts of an ecosystem), question 1 to q7
14–16	easy	003	what does X depend on Y for	a manatee; a chickadee; a bluebird	Lesson 3 (How a living thing depends on other living things), question 1 to q5
17–19	easy	005	which thing not alive does X depend on	a groundhog's burrow; a dolphin breathing; duckweed's roots hanging in the lake (8 Oct review: the tortoise was Lesson 4 (How a living thing depends on things that are not alive), question 7's scene; the duckweed-makes-food stem was Lesson 4 (How a living thing depends on things that are not alive), question 3 with the plant renamed)	Lesson 4 (How a living thing depends on things that are not alive), question 1 to q6
20–25	easy	004	how do the two affect each other	bear and salmon; bison and pronghorn; ants and aphids; ladybug and aphids; butterfly and apple tree; seals and sea lions	Lesson 5 (How two living things affect each other), question 1 to q6
26	medium	001	why the water belongs	a marsh	Lesson 1 (What an ecosystem is: living things and the things they use, together), question 2 (the reef's water, yes / no)
27–30	medium	002	the once-alive boundary: the word; the biotic-though-dead part; the reason; the mixed pair	a fallen log; a dead crab; a pine needle; a rattlesnake and a sand dune	Lesson 2 (Biotic or abiotic: sorting the parts of an ecosystem), question 2, q5, q7
31–35	medium	003	which living thing for food; the true sentence of a hunt; the sentence about a living thing; a place to hide; the cowbird's food	an armadillo; salmon and grizzly; a chipmunk; a quail and a bush; a cowbird on a bison	Lesson 3 (How a living thing depends on other living things), question 6, q7
36–39	medium	005	the thing not alive for oxygen; the sentence about a thing not alive (three times)	a clam; a snake on a sun-warmed rock; moss; a mountain goat on a rock face (8 Oct review: the snake's road was a man-made thing Lesson 1 (What an ecosystem is: living things and the things they use, together) had ruled out; the goats' "salt" stem named its own answer and sat outside the taught set)	Lesson 4 (How a living thing depends on things that are not alive), question 4, q7, q8
40–42	medium	004	predator or prey named; the word pair	bat and moth; pelican and fish; garter snake and slug	Lesson 5 (How two living things affect each other), question 7, q8
43–45	medium	004	the pair that both need the same food; why two bluebirds affect each other; a tick on a dog sorted	gulls and clams; two bluebirds; a tick and a dog	Lesson 5 (How two living things affect each other), question 3, q4
46–47	hard	001, 002	the TWO things not alive that belong; the TWO abiotic parts (multis)	a Maine shore; a small river	Lesson 1 (What an ecosystem is: living things and the things they use, together), question 2 / Lesson 2 (Biotic or abiotic: sorting the parts of an ecosystem), question 8
48–49	hard	003	only a place to hide; the one living thing among four used	a young trout under roots; a kingfisher	Lesson 3 (How a living thing depends on other living things), question 6
50–51	hard	005	who loses the thing it breathed; the word water produced	a shrinking Texas lake; a bass	Lesson 4 (How a living thing depends on things that are not alive), question 4
52–54	hard	004	which of four eaters is a predator; the matching pair; the TWO eats pairs (multi)	a toad among grass-eaters; loons and ospreys; moose, wolf, elk and bear	Lesson 5 (How two living things affect each other), question 9, q3, q1
55–58	hard	004	the term produced (predator ×2, prey ×2)	coyote and ground squirrel; pike and perch (8 Oct review: the shark and sea lion was Lesson 5 (How two living things affect each other), question 8's shark and seal renamed); lynx and hare	Lesson 5 (How two living things affect each other), question 11, q12
59	hard	001	Willa's claim: the correct reason	a swamp	Lesson 1 (What an ecosystem is: living things and the things they use, together), question 8 (Willa, yes / no)