Air and why we need it

Tests: 4 of 13 right · Exam: 0 of 4 right · Kind: ★ · Understood: 10 of 17 · Run: 2026-10-18, commit f3c23ea72

Lesson 17 of the world 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 · ★ · wrong ✗

If all green plants disappeared, what would slowly happen to the air?

1. It would get more and more oxygen — ← Mova's choice · score 4
2. Its oxygen would run low and its carbon dioxide would grow — ✓ the right answer · no support
3. Nothing, because animals make oxygen — no support
4. It would all turn into water vapour — no support

Why: It took the question to ask what happens next. It chose option 1 with score 4, the only option with support. Its support: lesson 17, line 11: «The air we breathe out has less oxygen and more carbon dioxide and water vapour than the air we breathe in, but it still has some oxygen.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «air» (+2); the same thing acted on «oxygen» (+2). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 2 · ★ · wrong ✗

Why does blowing gently on a dying campfire make it burn brighter?

1. Your warm breath heats the wood — no support
2. It brings the fire more oxygen — ✓ the right answer · no support
3. It cools the wood so it burns better — ← Mova's choice · score 1
4. Your breath is full of fuel — no support

Why: It took the question to ask why something happens (its cause). It chose option 3 with score 1, the only option with support. Its support: lesson 16, line 12: «The sea warms up and cools down slowly, so it makes the climate of coasts milder.», reached through the cause of the sentence the question matched. What matched: the same action «cool down» (+2). Against it: a different doer (counts against) (-1). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 3 · ★ · right ✓

Which is true about the air you breathe out?

1. It still has some oxygen, but less than before — ← Mova's choice · ✓ the right answer · score 7
2. It has no oxygen in it at all — score 7
3. It has more oxygen than the air you breathed in — score 7
4. It is pure carbon dioxide — score 6

Why: It took the question to ask which statement is true. It chose option 1 with score 7, tied with another option at 7 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 17, line 11: «The air we breathe out has less oxygen and more carbon dioxide and water vapour than the air we breathe in, but it still has some oxygen.», reached through the same lesson line as the sentence the question matched. What matched: the same doer «air» (+4); the same thing acted on «less oxygen» (+2); the same light verb (be, have, do, get, go) (+1). · the question and its options parsed, with trees and pragmatics

Test 4 · ★ · wrong ✗

Why is it hard to run fast near the top of a very high mountain?

1. Gravity is much stronger up there — ← Mova's choice · no support
2. Each breath brings in less oxygen — ✓ the right answer · no support
3. The ground is softer up there — no support
4. The air is too heavy to breathe — 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 ✗

A water plant grows in a goldfish bowl near a window. How does it help the fish?

1. It warms the water up for the fish at night — no support
2. It makes the water salty, just like the sea — ← Mova's choice · score 6
3. It adds oxygen to the water in the light — ✓ the right answer · score 6
4. It keeps the water cold, like ice from a fridge — no support

Why: It took the question to ask what something is like. It chose option 2 with score 6, tied with another option at 6 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 17, line 12: «Plants take in carbon dioxide and give out oxygen when they make food in sunlight.», reached through the remembered sentence the question matched. What matched: the same action «make» (+4); the same doer «plants» (+4). Against it: a different thing acted on (counts against) (-2). The right option, 3, scored 6. · the question and its options parsed, with trees and pragmatics

Test 6 · ★ · wrong ✗

Which shows that air takes up space?

1. A stone sinks to the bottom of a pond — no support
2. Ice melts in a warm room — ← Mova's choice · score 6
3. A cup fills up when you pour water in — no support
4. A glass pushed upside down into water stays partly dry inside — ✓ the right answer · score 4

Why: It took the question to ask who or what does it. It chose option 2 with score 6, against 4 for the next best. Its support: lesson 12, line 14: «Water expands when it freezes, so ice takes up more space than the water it came from.», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+4); the same doer «ice» (+3). Against it: a different action (counts against) (-1). The right option, 4, scored 4. · the question and its options parsed, with trees and pragmatics

Test 7 · ★ · right ✓

Why must a car engine have air coming in?

1. The air keeps the seats nice and cool — no support
2. The engine runs on nitrogen gas — no support
3. Air is the only fuel that it ever uses — no support
4. The fuel needs oxygen to burn — ← Mova's choice · ✓ the right answer · score 4

Why: It took the question to ask why something happens (its cause). It chose option 4 with score 4, the only option with support. Its support: lesson 17, line 13: «Burning needs oxygen; without it a fire goes out, and a car engine, which burns fuel, needs air coming in for the same reason.», reached through the same lesson line as the sentence the question matched. What matched: the same action «need» (+2); the same thing acted on «oxygen» (+2). · the question and its options parsed, with trees and pragmatics

Test 8 · ★ · right ✓

Which gas do both a candle flame and a person need?

1. Nitrogen — score 6
2. Helium — no support
3. Carbon dioxide — no support
4. Oxygen — ← Mova's choice · ✓ the right answer · score 14

Why: It took the question to ask what it is done to. It chose option 4 with score 14, against 6 for the next best. Its support: lesson 17, line 13: «Burning needs oxygen; without it a fire goes out, and a car engine, which burns fuel, needs air coming in for the same reason.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+6); the same action «need» (+4); the same thing acted on «oxygen» (+4). · the question and its options parsed, with trees and pragmatics

Test 9 · ★ · wrong ✗

Which list goes from the most to the least in the air?

1. Oxygen, nitrogen, carbon dioxide — ← Mova's choice · no support
2. Carbon dioxide, oxygen, nitrogen — no support
3. Nitrogen, oxygen, carbon dioxide — ✓ the right answer · no support
4. Oxygen, carbon dioxide, nitrogen — 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 10 · ★ · wrong ✗

what's air actually made of mostly

1. Oxygen and carbon dioxide — ← Mova's choice · no support
2. Nitrogen and oxygen — ✓ the right answer · no support
3. Mostly carbon dioxide — no support
4. Mostly water vapour — 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 11 · ★ · wrong ✗

why's the candle go out when u put a jar over it

1. The jar makes it too cold — ← Mova's choice · no support
2. The smoke pushes the flame down — no support
3. It uses up the oxygen it needs to burn — ✓ the right answer · no support
4. The glass blocks the light it needs — 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 12 · ★ · right ✓

Mia says air is mostly oxygen. true?

1. No, most of the air is carbon dioxide — no support
2. Yes, nearly all the air is oxygen — score 4
3. No, only about one fifth is oxygen; most is nitrogen — ← Mova's choice · ✓ the right answer · score 5
4. Yes, about half the air is oxygen — score 4

Why: It took the question to ask which statement is true. It chose option 3 with score 5, against 4 for the next best. Its support: lesson 17, line 8: «About one fifth of the air is oxygen.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «one fifth» (+2); the same thing acted on «oxygen» (+2); the same light verb (be, have, do, get, go) (+1). · the question and its options parsed, with trees and pragmatics

Test 13 · ★ · wrong ✗

my brother says the air u breathe out has no oxygen left. right?

1. No, it has more oxygen than the air we breathe in — ← Mova's choice · score 6
2. Yes, we use up every bit of oxygen — no support
3. No, it has less oxygen but still some — ✓ the right answer · score 5
4. Yes, it's all carbon dioxide — score 4

Why: It took the question to ask which statement is true. It chose option 1 with score 6, against 5 for the next best. Its support: lesson 17, line 11: «The air we breathe out has less oxygen and more carbon dioxide and water vapour than the air we breathe in, but it still has some oxygen.», reached through the same lesson line as the sentence the question matched. What matched: the same action «breathe in» (+4); the same thing acted on «air» (+2). The right option, 3, scored 5. · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · wrong ✗

State the approximate proportion of the air composed of oxygen.

1. Four fifths — ← Mova's choice · no support
2. One hundredth — no support
3. One fifth — ✓ the right answer · no support
4. One half — 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 · wrong ✗

Identify the principal constituent gas of the atmosphere.

1. Oxygen — ← Mova's choice · no support
2. Water vapour — no support
3. Carbon dioxide — no support
4. Nitrogen — ✓ 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 3 · formal language · wrong ✗

Select the response that is consistent with the established facts concerning exhaled air.

1. It contains no oxygen whatsoever — ← Mova's choice · no support
2. It contains less oxygen and more carbon dioxide than inhaled air, yet some oxygen remains — ✓ the right answer · no support
3. It consists entirely of carbon dioxide, the whole of the oxygen having been consumed in the lungs — no support
4. It contains more oxygen than inhaled air — 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 ✗

Whereas a fire is deprived of oxygen, determine the consequence.

1. The fire burns more fiercely — no support
2. The fire is extinguished — ✓ the right answer · no support
3. The fire is unaffected — no support
4. The fire produces oxygen of its own — ← Mova's choice · score 3

Why: It took the question to ask which statement is true. It chose option 4 with score 3, the only option with support. Its support: lesson 17, line 4: «Fire needs oxygen too: a flame goes out when its air is cut off, which is how a fire blanket smothers a fire.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «fire» (+2); the same thing acted on «oxygen» (+2). Against it: a different action (counts against) (-1). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/world/17-air-oxygen-carbon-dioxide/