Rice, maize and potatoes: the plants that feed the world

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

Lesson 345 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 · ★ · wrong ✗

Count them: a corn cob has 16 rows with 40 kernels in each. How many kernels and how many silk threads did it once have?

1. 56 kernels and 56 silks — ← Mova's choice · score 6
2. 640 kernels and 40 silks — score 6
3. 640 kernels and 16 silks — score 6
4. 640 kernels and 640 silks — ✓ the right answer · score 6

Why: It took the question to ask what it is done to. It chose option 1 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 345, line 10: «Corn cobs nearly always have an even number of rows, often 12 to 20, because the kernels grow in pairs, and one cob carries about 500 to 800 kernels.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+4); the same thing acted on «500 kernels» (+2). The right option, 4, scored 6. · the question and its options parsed, with trees and pragmatics

Test 2 · ★ · wrong ✗

«found a cob with 15 rows, bet that's normal» What is the best answer?

1. Yes, odd numbers of rows are the most common kind of all — ← Mova's choice · score 6
2. Rows have nothing to do with pairs — score 3
3. All cobs have exactly 15 rows — score 6
4. It would be very unusual, because kernels grow in pairs — ✓ the right answer · score 5

Why: It took the question to ask what it is done to. It chose option 1 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 345, line 2: «Maize, or corn, is a grass too. Peel back the husk and each long silky thread leads to one kernel; pollen from the feathery tassel on top must land on that sil…», reached through a sentence linked to the one the question matched. What matched: it fills the role the question asks for (+4); the same thing acted on «number» (+3). Against it: a different doer (counts against) (-1). The right option, 4, scored 5. · the question and its options parsed, with trees and pragmatics

Test 3 · ★ · wrong ✗

A farmer finds a cob with lots of gaps where kernels are missing. What does it tell him?

1. The cob was too cold — ← Mova's choice · no support
2. The cob grew too fast — no support
3. Mice stole the kernels at night — no support
4. Those silks got no pollen — ✓ 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 ✓

If one grain of rice gives a thousand, how many would ten grains give?

1. Ten thousand — ← Mova's choice · ✓ the right answer · score 4
2. One thousand — no support
3. Ten — no support
4. One hundred — no support

Why: It took the question to ask what it is done to. It chose option 1 with score 4, the only option with support. Its support: lesson 345, line 4: «Every grain of rice or kernel of maize is a seed with a tiny baby plant inside, which is why one grain planted can give back hundreds or even thousands.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+4); the same thing acted on «hundreds» (+2). Against it: a different action (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Test 5 · ★ · wrong ✗

«spuds are just roots innit» What is the true answer?

1. Yes, they are roots, the same as carrots and parsnips — ← Mova's choice · no support
2. No, a potato is a swollen underground stem — ✓ the right answer · no support
3. No, they are seeds — no support
4. No, they are fruits — 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 · ★ · wrong ✗

In a cartoon, a cheeky potato with eyes and arms sprouts in a sunny window and the kid eats it raw, green bits and all. What is the danger?

1. Nothing, green potatoes are healthiest — no support
2. The eyes will see inside your tummy — no support
3. Green parts and sprouts hold a natural poison that can upset your tummy — ✓ the right answer · score 1
4. Raw potatoes turn into chips inside you — ← Mova's choice · score 3

Why: It took the question to ask what it is done to. It chose option 4 with score 3, against 1 for the next best. Its support: lesson 338, line 4: «In cartoons potatoes grow on trees and carrots wink from bushes. Real plants hide their stores underground, and some close relatives, like potatoes and tomatoe…», reached through the remembered sentence the question matched. What matched: the same action «grow» (+3). The right option, 3, scored 1. · the question and its options parsed, with trees and pragmatics

Test 7 · ★ · right ✓

Why should a sack of potatoes be kept in a dark cupboard?

1. Light makes them turn green and produce poison — ← Mova's choice · ✓ the right answer · no support
2. Light melts their skins — no support
3. The dark makes them grow much bigger in the sack — no support
4. Potatoes are afraid of light — 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 · ★ · right ✓

«white rice is better, it's cleaner» What is the fairest reply?

1. White rice has more vitamins than brown, because the polishing adds extra goodness to it — no support
2. Brown rice is just dirty white rice — score 4
3. White rice cooks faster and keeps longer, but the bran it lost held vitamin B1 — ← Mova's choice · ✓ the right answer · score 5
4. They are exactly the same in every way — no support

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 345, line 8: «White rice is brown rice with the outer layers, called bran, polished off; it cooks faster and keeps longer, but the bran held vitamin B1.», reached through the same lesson line as the sentence the question matched. What matched: the same action «hold» (+4); the same thing acted on «vitamin» (+1). · the question and its options parsed, with trees and pragmatics

Test 9 · ★ · right ✓

How did farmers without science books turn a scruffy wild grass into big soft corn cobs?

1. They poured special magic water on the wild grass every morning until it grew cobs — score 6
2. They kept seeds from their best plants year after year for thousands of years — ← Mova's choice · ✓ the right answer · score 10
3. They crossed it with apple trees — score 1
4. A single farmer did it in one summer — no support

Why: It took the question to ask what something is like. It chose option 2 with score 10, against 6 for the next best. Its support: lesson 286, line 12: «Ploughing turns the soil and buries weeds, but many farmers now plough less to keep the soil, its worms and its microbes from drying and blowing away.», reached through a sentence linked to the one the question matched. What matched: the same action «keep» (+5); the same doer «many farmers» (+4); a different thing acted on (counts against) (+1). · the question and its options parsed, with trees and pragmatics

Test 10 · ★ · wrong ✗

Why might a plant that keeps its food underground cope well with cold mountain weather?

1. Cold makes potatoes grow faster — ← Mova's choice · score 4
2. Underground plants do not need water — score 4
3. The soil protects its stored food from frost — ✓ the right answer · score 1
4. Mountain air is always warm, even at the very top — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 4, tied with another option at 4 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 338, line 9: «Potatoes that turn green in the light have a bitter poison, and the green part must not be eaten, so potatoes are kept in the dark.», reached through the same lesson line as the sentence the question matched. What matched: the same action «turn» (+4). The right option, 3, scored 1. · the question and its options parsed, with trees and pragmatics

Test 11 · ★ · wrong ✗

Why are rice fields on hills built as steps?

1. Each flat step can hold water — ✓ the right answer · no support
2. Steps keep the rice dry — no support
3. Steps make it easier to climb — score -1
4. Rice grows only on stairs — ← Mova's choice · score 0

Why: It took the question to ask why something happens (its cause). It chose option 4 with score 0, against -1 for the next best. Its support: lesson 345, line 5: «Rice can grow in flooded fields because air passes down spongy tubes in its stems to the roots, and flooding drowns many weeds; some farmers keep ducks or fish…», reached through the option's own match among the sentences about the question's things. The right option, 1, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 12 · ★ · wrong ✗

In Ice Age, Scrat chases an acorn. If he had a corn cob instead and planted every kernel, what would grow?

1. Nothing would grow, because corn kernels are only food and not seeds — ← Mova's choice · score 6
2. One big oak tree — no support
3. A field of potatoes — no support
4. A maize plant from each kernel, because each kernel is a seed — ✓ the right answer · score 6

Why: It took the question to ask who or what does it. It chose option 1 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 345, line 10: «Corn cobs nearly always have an even number of rows, often 12 to 20, because the kernels grow in pairs, and one cob carries about 500 to 800 kernels.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+4); the same doer «kernels» (+2). The right option, 4, scored 6. · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · right ✓

Identify the means by which the rice plant obtains air for its roots while standing in flooded fields.

1. Air is supplied by the farmer through pipes — no support
2. Air is conveyed downward through spongy tissue within the stems — ← Mova's choice · ✓ the right answer · score 3
3. The plant does not require air at any stage — score 2
4. The roots extract oxygen from the water as a fish does — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 3, against 2 for the next best. Its support: lesson 251, line 9: «The underside of a leaf has tiny holes called stomata that open to let air in and water vapour out; a big tree can lose hundreds of litres of water on a hot da…», reached through the option's own match among the sentences about the question's things. What matched: the same circumstance (+2); the same thing acted on «air» (+1). · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · right ✓

Ascertain the reason for which the rows of kernels upon a cob of maize are ordinarily even in number.

1. Odd rows are removed by the farmer — no support
2. Odd rows are shed in the wind — no support
3. The number is determined by the colour of the cob — no support
4. The kernels develop in pairs from the outset — ← Mova's choice · ✓ the right answer · 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 345, line 10: «Corn cobs nearly always have an even number of rows, often 12 to 20, because the kernels grow in pairs, and one cob carries about 500 to 800 kernels.», reached through the remembered sentence the question matched. What matched: the same place «pairs» (+2). Against it: a different action (counts against) (-2); the same doer «kernels» (-3). · 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 origin of the potato?

1. It was brought to Europe by the Romans — ← Mova's choice · no support
2. It was first cultivated in the Andes of South America and brought to Europe by the Spanish in the sixteenth century — ✓ the right answer · no support
3. It was first cultivated in the deserts of North Africa — no support
4. It was first cultivated in Ireland — 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 ✗

Select the response consistent with the established facts concerning white rice.

1. It is brown rice from which the bran has been removed, with a consequent loss of vitamin B1 — ✓ the right answer · score 4
2. It contains more vitamins than brown rice — ← Mova's choice · score 6
3. It is a distinct species cultivated in cold regions — no support
4. It is brown rice that has been bleached with chalk — score 4

Why: It took the question to ask which statement is true. It chose option 2 with score 6, against 4 for the next best. Its support: lesson 345, line 8: «White rice is brown rice with the outer layers, called bran, polished off; it cooks faster and keeps longer, but the bran held vitamin B1.», reached through the same lesson line as the sentence the question matched. What matched: the same action «hold» (+4); the same thing acted on «vitamin» (+1); a different doer (counts against) (+1). The right option, 1, scored 4. · the question and its options parsed, with trees and pragmatics

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