Soil and what lives in it

Tests: 5 of 12 right · Exam: 2 of 4 right · Kind: plain · Understood: 11 of 16 · Run: 2026-10-18, commit f3c23ea72

Lesson 63 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 · right ✓

A gardener pours a jug of water on two pots. The water runs out of one pot almost at once but stays on top of the other for a long time. Which pot has clay soil?

1. The one where the water runs out at once — score 6
2. Neither, because clay lets water through fastest — score 2
3. Both have clay soil — no support
4. The one where the water stays on top — ← Mova's choice · ✓ the right answer · score 11

Why: It took the question to ask who or what does it. It chose option 4 with score 11, against 6 for the next best. Its support: lesson 60, line 2: «Heat moves from hotter things to colder things. Metals are good conductors of heat, so heat travels quickly along a metal spoon in hot tea up to your fingers;…», reached through the remembered sentence the question matched. What matched: the same place «top» (+6); the same action «stay» (+4); a different doer (counts against) (+1). · the question and its options parsed, with trees and pragmatics

Test 2 · wrong ✗

Which is true about a forest floor?

1. The leaves are all blown away by the wind each winter — ← Mova's choice · no support
2. The trees take the dead leaves back into their trunks — no support
3. Fallen leaves stay there forever because nothing eats them — no support
4. Fallen leaves are broken down by fungi, bacteria and small animals into humus — ✓ 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 3 · wrong ✗

A farmer ploughs a field on a slope and leaves it bare all winter. What is most likely to happen?

1. The soil turns into loam on its own — no support
2. The soil grows thicker by spring — no support
3. Worms move to the field from far away — ← Mova's choice · score 2
4. Rain washes much of the topsoil away — ✓ the right answer · score 2

Why: It took the question to ask which statement is true. It chose option 3 with score 2, tied with another option at 2 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 47, line 9: «Rich farm soil, like that of the American Great Plains, takes thousands of years to form, and wind and rain can carry it away quickly from bare fields.», reached through the option's own match among the sentences about the question's things. What matched: the same property (+2); the same circumstance (+2). Against it: a different action (counts against) (-1); a different doer (counts against) (-1). The right option, 4, scored 2. · the question and its options parsed, with trees and pragmatics

Test 4 · right ✓

If all the decomposers in a wood disappeared, what would happen?

1. The soil would become richer and richer every year as the dead things piled up — score -1
2. Dead leaves and bodies would pile up and the soil would lose its nutrients — ← Mova's choice · ✓ the right answer · score 1
3. The trees would grow faster than ever — no support
4. Nothing would change at all — no support

Why: It took the question to ask what happens next. It chose option 2 with score 1, against -1 for the next best. Its support: lesson 63, line 9: «Decomposers such as fungi, bacteria and earthworms break down dead matter and return nutrients to the soil.», reached through what followed the sentence the question matched. What matched: the same thing acted on «nutrients» (+4). Against it: a different doer (counts against) (-1); a different action (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Test 5 · wrong ✗

Why is it a problem when a flood carries away a field's topsoil?

1. Plants grow only in the rock below — ← Mova's choice · no support
2. It took hundreds of years to form and holds most of the nutrients — ✓ the right answer · no support
3. Topsoil is easy to make again in a week — no support
4. The subsoil below is much richer anyway — 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 ✓

A child digs a deep hole in a garden. The soil at the top is dark, lower down it is paler and stonier, and at the bottom there is rock. Why is the top darkest?

1. It holds the most humus from rotted plants — ← Mova's choice · ✓ the right answer · score 3
2. The sunlight has burned it dark over the years — no support
3. It is the oldest layer of all, so it is darkest — no support
4. It is wetter from all the rain that falls on it — no support

Why: It took the question to ask why something happens (its cause). It chose option 1 with score 3, the only option with support. Its support: lesson 43, line 20: «Some rock high in mountains formed long ago under the sea and was pushed up when plates collided, so it can hold shells of sea animals.», reached through the option's own match among the sentences about the question's things. What matched: the same action «hold» (+2); the same doer «rock» (+1). · the question and its options parsed, with trees and pragmatics

Test 7 · right ✓

Which one does the most to keep soil airy and well drained in a garden?

1. Earthworms digging tunnels — ← Mova's choice · ✓ the right answer · no support
2. Snails eating leaves — no support
3. Bees visiting flowers — no support
4. Birds pulling up worms to eat — 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 8 · wrong ✗

A pupil puts banana peel and a plastic bag in a compost heap. After some months, what will he find?

1. Both are exactly as they were — no support
2. The peel has rotted away but the bag is still there — ✓ the right answer · no support
3. Both have rotted away into humus — no support
4. The bag has rotted but the peel is still there — ← Mova's choice · score 2

Why: It took the question to ask what it is done to. It chose option 4 with score 2, the only option with support. Its support: lesson 57, line 3: «Plastic is a big problem because it takes hundreds of years to break down. A plastic bag in the sea can be mistaken for a jellyfish and swallowed by a turtle.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+3); the same thing acted on «plastic bag» (+1). Against it: a different action (counts against) (-2). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 9 · right ✓

why's there worms everywhere after rain, are they even good for the soil

1. Yes, but only because they eat the weeds — no support
2. No, they make the soil too hard to dig — score 4
3. Yes, their tunnels let air and water into the soil — ← Mova's choice · ✓ the right answer · score 10
4. No, they eat the plant roots and harm the soil badly — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 10, against 4 for the next best. Its support: lesson 63, line 10: «Earthworm tunnels let air and water into the soil.», reached through the remembered sentence the question matched. What matched: the same place «soil» (+4); the same action «let» (+3); the same doer «earthworm tunnels» (+2); the same thing acted on «air» (+1). · the question and its options parsed, with trees and pragmatics

Test 10 · wrong ✗

our garden's clay and it stays soggy for ages, why

1. Clay soil is always below freezing in winter — ← Mova's choice · no support
2. Clay soil has no air in it at all, only water — no support
3. Clay soil holds water and drains slowly — ✓ the right answer · no support
4. Clay soil soaks up rain straight from the 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

Test 11 · wrong ✗

my sister says soil is just crushed up rock and nothing else. right?

1. Yes, soil is only broken rock and nothing more — no support
2. No, soil also has humus, water, air and living things — ✓ the right answer · score 3
3. Yes, but only the soil under the topsoil — no support
4. No, soil is mostly made of old leaves only — ← Mova's choice · score 4

Why: It took the question to ask which statement is true. It chose option 4 with score 4, against 3 for the next best. Its support: lesson 63, line 6: «Soil is made of broken rock, humus, water, air and living things.», reached through the remembered sentence the question matched. What matched: the same action «make» (+3); the same thing acted on «soil» (+1). The right option, 2, scored 3. · the question and its options parsed, with trees and pragmatics

Test 12 · wrong ✗

Sam reckons if u dig up the plants the soil stays put no problem. true?

1. Yes, soil never moves once it has formed — score 2
2. Yes, plant roots actually loosen soil and help it wash away — score 2
3. No, the soil would turn straight into solid rock — ← Mova's choice · score 5
4. No, bare soil is easily washed or blown away without roots — ✓ the right answer · 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 63, line 5: «Soils differ: sandy soil has big grains with big gaps, so water drains through it fast; clay soil has tiny grains packed close, so it holds water and can becom…», reached through the remembered sentence the question matched. What matched: the same action «become» (+3); the same doer «soil» (+2). The right option, 4, scored 4. · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · wrong ✗

Which of the following statements most accurately characterises humus?

1. Water held between grains of clay — ← Mova's choice · score 5
2. Small fragments of rock without any nutrients — no support
3. Dark material formed from rotted plants and animals, rich in nutrients — ✓ the right answer · no support
4. The solid rock beneath the subsoil — no support

Why: It took the question to ask who or what does it. It chose option 1 with score 5, the only option with support. Its support: lesson 61, line 4: «A fossil is the remains or trace of a living thing from long ago kept in rock. Most fossils form when a dead plant or animal is quickly buried in mud or sand;…», reached through the same lesson line as the sentence the question matched. What matched: the same action «keep» (+3); the same thing acted on «living thing» (+2). The right option, 3, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · right ✓

Identify the function performed by decomposers such as fungi, bacteria and earthworms.

1. They manufacture soil from solid rock within a single day — no support
2. They remove all air and water from the soil — score 2
3. They break down dead matter and return nutrients to the soil — ← Mova's choice · ✓ the right answer · score 10
4. They consume the roots of living plants exclusively and nothing else — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 10, against 2 for the next best. Its support: lesson 63, line 9: «Decomposers such as fungi, bacteria and earthworms break down dead matter and return nutrients to the soil.», reached through the remembered sentence the question matched. What matched: the same place «soil» (+4); the same action «return» (+3); the same doer «decomposers» (+2); the same thing acted on «nutrients» (+1). · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · right ✓

It is given that one soil drains rapidly whilst another retains water and drains slowly. Determine the respective designations of these soils.

1. Subsoil and topsoil respectively — no support
2. Clay soil and sandy soil respectively — no support
3. Sandy soil and clay soil respectively — ← Mova's choice · ✓ the right answer · score 4
4. Loam and subsoil respectively — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 4, the only option with support. Its support: lesson 63, line 11: «Sandy soil drains water quickly; clay soil holds water and drains slowly.», reached through the remembered sentence the question matched. What matched: the same doer «sandy soil» (+2); the same property (+2). · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · wrong ✗

Select the response that is consistent with the established facts concerning the cause of soil erosion.

1. Earthworm tunnels cause the soil to collapse — ← Mova's choice · no support
2. Humus causes the soil to dissolve in rain — no support
3. Bare soil without roots is readily washed or blown away — ✓ the right answer · no support
4. Plant roots loosen the soil and carry it off — 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

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