The Amazon forest floor: leafcutters, army ants, tapirs, jaguars and the giant spider

Tests: 8 of 11 right · Exam: 1 of 4 right · Kind: plain · Understood: 8 of 15 · Run: 2026-10-18, commit f3c23ea72

Lesson 157 of the biology course of Mova's primary school, as Mova's small model took its tests: it had read this lesson and the ones before it and learned from their exercises. Each test shows the options in the order the student saw them, its choice, the right answer, the score of every option and why it chose. The lesson itself, sentence by sentence with trees and pragmatics: the lesson in the corpora.

Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: the lesson's questions in the corpora.

Test 1 · right ✓

In a cartoon a cat runs screaming from a bath. What is true of the jaguar?

1. It loves water and swims to hunt caimans and fish — ← Mova's choice · ✓ the right answer · score 10
2. Jaguars cannot swim — score 5
3. All cats sink in water — score 2
4. Jaguars never go near water, because their fur would get too heavy — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 10, against 5 for the next best. Its support: lesson 157, line 4: «In cartoons cats hate water, like Tom shaking his wet fur; the jaguar loves rivers and swims to catch caimans, a kind of crocodile, and fish.», reached through the same lesson line as the sentence the question matched. What matched: the same action «swim» (+5); the same doer «jaguar» (+3); its «because» matches the remembered cause (+2). · the question and its options parsed, with trees and pragmatics

Test 2 · right ✓

«that ant line's carrying salad for dinner» What is right?

1. Yes, ants love leaf salad — no support
2. They are building a leafy roof — no support
3. They are carrying leaves to grow fungus, which is what they eat — ← Mova's choice · ✓ the right answer · score 6
4. They are taking the leaves down to the river to make little boats — score 5

Why: It took the question to ask which statement is true. It chose option 3 with score 6, against 5 for the next best. Its support: lesson 157, line 5: «Leafcutter ants cut and carry leaves but do not eat them; they grow a fungus on chewed leaf paste and eat the fungus.», reached through the same lesson line as the sentence the question matched. What matched: the same action «grow» (+5); the same thing acted on «fungus» (+1). · the question and its options parsed, with trees and pragmatics

Test 3 · wrong ✗

A spider has 8 legs. Two Goliath birdeaters sit on a log, and a third one comes. How many legs?

1. 16 — ← Mova's choice · no support
2. 32 — no support
3. 18 — no support
4. 24 — ✓ the right answer · no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 4 · right ✓

A tapir and a jaguar stand by a stream. How many legs and tails altogether?

1. 8 legs and 2 tails — ← Mova's choice · ✓ the right answer · no support
2. 4 legs and 2 tails — no support
3. 6 legs and 2 tails — no support
4. 8 legs and 1 tail — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 5 · wrong ✗

«it's a pig with a nose like an elephant» Which is right about the tapir?

1. It is a wild pig — ← Mova's choice · no support
2. It is a kind of anteater with a short trunk for licking up ants — no support
3. It looks piggy but is a closer cousin of horses and rhinos — ✓ the right answer · no support
4. It is a baby elephant — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 6 · right ✓

What would happen if agoutis disappeared from the forest?

1. Nothing would happen — no support
2. More Brazil nuts would fall — score 4
3. Fewer Brazil nut seeds would be planted, and fewer new trees would grow — ← Mova's choice · ✓ the right answer · score 6
4. Brazil nut trees would grow faster with nobody taking their nuts away and burying them — score 4

Why: It took the question to ask what happens next. It chose option 3 with score 6, against 4 for the next best. Its support: lesson 157, line 16: «Agoutis open hard Brazil nut pods and bury spare seeds, and the forgotten seeds grow into new Brazil nut trees.», reached through what followed the sentence the question matched. What matched: the same doer «agoutis» (+4); the same thing acted on «spare seeds» (+4). Against it: a different action (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Test 7 · right ✓

«a birdeater?? so it eats birds every day lol» What is right?

1. Yes, a bird for every meal — no support
2. Despite its name it mostly eats insects, worms and frogs — ← Mova's choice · ✓ the right answer · score 8
3. It eats only bird eggs — score 1
4. It eats only parrots — score 1

Why: It took the question to ask which statement is true. It chose option 2 with score 8, against 1 for the next best. Its support: lesson 157, line 12: «The Goliath birdeater is the heaviest spider in the world, with a leg span like a dinner plate, and mostly eats insects, worms and frogs, only rarely a bird.», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «insects» (+3); the same property (+3); the same action «eat» (+2). · the question and its options parsed, with trees and pragmatics

Test 8 · wrong ✗

A man stung by a bullet ant says it felt like being shot. What is true?

1. Bullet ants shoot real bullets — ← Mova's choice · no support
2. Its sting is one of the most painful known, and the pain lasts hours — ✓ the right answer · no support
3. He is joking, it just feels like a tiny mosquito bite that is gone in a minute — no support
4. Bullet ants cannot sting — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 9 · right ✓

«why don't the trees just grow deep roots like at home» What is the best answer?

1. Deep roots would get eaten by jaguars — score -2
2. The rich layer of soil is thin, so roots spread wide and buttresses hold the tree up — ← Mova's choice · ✓ the right answer · score 4
3. The trees are too short to need deep roots, so they never grow them and just lean on each other — score 0
4. Their roots are too lazy — no support

Why: It took the question to ask why something happens (its cause). It chose option 2 with score 4, against 0 for the next best. Its support: lesson 3, line 10: «Rainforest soil is thin, so roots stay near the surface, and many tall trees grow wide buttress roots that prop them up like the walls of a tent.», reached through the same lesson line as the sentence the question matched. What matched: the same doer «wide buttress roots» (+2); the same property (+2). · the question and its options parsed, with trees and pragmatics

Test 10 · right ✓

A glass frog sleeps on a leaf and turns even more see-through. How?

1. It drinks lots of water — score 2
2. It turns off its heart — no support
3. It peels off its skin — no support
4. It hides most of its red blood in its liver — ← Mova's choice · ✓ the right answer · score 12

Why: It took the question to ask which statement is true. It chose option 4 with score 12, against 2 for the next best. Its support: lesson 89, line 17: «Glass frogs have see-through bellies, and in 2022 scientists found that a sleeping glass frog hides most of its red blood in its liver to look almost clear.», reached through the same lesson line as the sentence the question matched. What matched: the same action «hide» (+5); the same doer «glass frog» (+3); the same place «liver» (+3); the same thing acted on «most» (+1). · the question and its options parsed, with trees and pragmatics

Test 11 · right ✓

Antbirds dart about at the front of an army ant swarm. What are they doing?

1. Fighting the ants to take over their nest — score 4
2. Eating the army ants one by one as they march — score 9
3. Snatching insects that flee the ants — ← Mova's choice · ✓ the right answer · score 10
4. Leading the ants like a guide through the forest — score 4

Why: It took the question to ask what is done. It chose option 3 with score 10, against 9 for the next best. Its support: lesson 157, line 7: «Army ants raid in a moving carpet of hundreds of thousands, and antbirds follow to catch the insects fleeing in front, not to eat the ants.», reached through the option's own match among the sentences about the question's things. What matched: it fills the role the question asks for (+4); the same action «flee» (+3); the same doer «insects» (+3). · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · wrong ✗

Select the response consistent with the established facts concerning the diet of leafcutter ants.

1. They subsist upon other insects exclusively — ← Mova's choice · no support
2. They subsist upon the leaves which they carry — no support
3. They subsist upon the sap of trees — no support
4. They subsist upon a fungus cultivated upon chewed leaf material — ✓ the right answer · no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · right ✓

Identify the principal reason for which a fallen tree disappears within a few years upon the floor of the rainforest.

1. Decomposition by fungi, termites and bacteria proceeds rapidly in heat and moisture — ← Mova's choice · ✓ the right answer · score 2
2. Submersion of the material beneath the soil by its own weight over a great many years — no support
3. Consumption by jaguars — no support
4. Removal by large mammals for nesting material — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 2, the only option with support. Its support: lesson 12, line 2: «Kick through autumn leaves and you are walking on next year's soil: fungi and tiny creatures rot the leaves and dead wood back into food for the trees.», reached through the option's own match among the sentences about the question's things. What matched: the same action «rot» (+2). · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · wrong ✗

Which of the following statements most accurately characterises the relationships of the tapir?

1. It is a member of the family of pigs — ← Mova's choice · no support
2. It is a juvenile form of the elephant — no support
3. It is a variety of anteater — no support
4. It is more closely related to the horse and the rhinoceros than to the pig — ✓ the right answer · no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · wrong ✗

Ascertain the principal function of the buttress roots of rainforest trees.

1. They capture fruit falling from the canopy — ← Mova's choice · no support
2. They support the tall tree in a thin layer of soil by spreading widely — ✓ the right answer · no support
3. They repel animals that would gnaw the trunk by means of long sharp spines — no support
4. They store water against prolonged drought — no support

Why: Nothing it remembers matched the question, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/biology/157-the-amazon-forest-floor/