Birds: feathers, wings, eggs and flight

Tests: 9 of 11 right · Exam: 1 of 4 right · Kind: plain · Understood: 10 of 15 · Run: 2026-10-18, commit f3c23ea72

Lesson 33 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 ✓

Your little brother finds a chick halfway out of its egg and wants to pull the shell off. What should you say?

1. Yes, help it, chicks cannot get out alone and will die without you — no support
2. Leave it, the chick is still using up its yolk and will do it itself — ← Mova's choice · ✓ the right answer · score 7
3. Shake the egg so it comes out faster — no support
4. Pour warm water on the shell — no support

Why: It took the question to ask what it is done to. It chose option 2 with score 7, the only option with support. Its support: lesson 33, line 9: «An egg has an air pocket at the wide end, white for water and cushioning, a yolk for food, and thousands of tiny holes in the shell that let air in; before it…», reached through the option's own match among the sentences about the question's things. What matched: the same action «take» (+4); the same doer «chick» (+4). Against it: a different thing acted on (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 2 · right ✓

In a cartoon a goose flies alone at the front for the whole trip. What really happens?

1. Geese never fly in groups at all, each one travels on its own — score 0
2. The youngest goose always leads — no support
3. The geese take turns at the tiring front place — ← Mova's choice · ✓ the right answer · score 8
4. The biggest goose always leads — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 8, against 0 for the next best. Its support: lesson 33, line 14: «Geese fly in a V because each bird rides the rising air from the wingtip of the bird in front, saving energy; they take turns at the front.», reached through the same lesson line as the sentence the question matched. What matched: the same action «take» (+5); the same thing acted on «turns» (+3). · the question and its options parsed, with trees and pragmatics

Test 3 · wrong ✗

my sister says the white bit of bird poo is calcium from eggshells. is it?

1. No, it is milk — ← Mova's choice · no support
2. Yes, birds poo out spare eggshell — no support
3. No, it is uric acid, the bird's version of wee — ✓ the right answer · no support
4. Yes, but only hens that lay eggs every day have it in their poo — 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 ✓

What would happen to a duck covered in oil from a spill at sea?

1. Its feathers would let water in and it would get soaked and cold — ← Mova's choice · ✓ the right answer · no support
2. It would float even better — no support
3. Nothing at all, as ducks are already oily, so a bit more does not matter — no support
4. It would fly faster — 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 ✗

If birds had heavy jaws full of teeth like crocodiles, what problem would they have?

1. They would have to live underwater — no support
2. They could not sing — ← Mova's choice · score 5
3. Nothing, teeth weigh nothing at all compared with the rest of the head — no support
4. Their heads would be heavy, making flight harder — ✓ the right answer · no support

Why: It took the question to ask what it is done to. It chose option 2 with score 5, the only option with support. Its support: lesson 33, line 18: «Most birdsong is sung by males to claim a territory, but European robins of both sexes sing in winter to defend their patch; birds sing loudest at dawn, when t…», reached through the option's own match among the sentences about the question's things. What matched: the same action «sing» (+4); the same doer «birds» (+4). Against it: one says «not», the other does not (counts against) (-3). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 6 · right ✓

A goose flies a little behind and to the side of the one in front. Why there?

1. It is the warmest spot in the flock — no support
2. That is where swirling air from the wingtip gives a lift — ← Mova's choice · ✓ the right answer · score 3
3. So it can talk to the goose in front — no support
4. So that it can steal bits of food from the leader's beak as they fly — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 3, the only option with support. Its support: lesson 33, line 14: «Geese fly in a V because each bird rides the rising air from the wingtip of the bird in front, saving energy; they take turns at the front.», reached through a sentence linked to the one the question matched. What matched: the same thing acted on «rising air» (+2); the same place «wingtip» (+2). Against it: a different action (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 7 · right ✓

shut it, birds aint dinosaurs, dinosaurs are all dead. who's right?

1. Birds evolved from dinosaurs, so scientists call them living dinosaurs — ← Mova's choice · ✓ the right answer · score 6
2. Birds are a kind of mammal — no support
3. Birds and dinosaurs are not related at all, they just look a bit alike — no support
4. Dinosaurs evolved from birds — score 3

Why: It took the question to ask which statement is true. It chose option 1 with score 6, against 3 for the next best. Its support: lesson 33, line 12: «Birds evolved from small feathered meat-eating dinosaurs, the same group as T. rex, so scientists count birds as living dinosaurs.», reached through the remembered sentence the question matched. What matched: the same circumstance (+3); the same doer «birds» (+2); the same action «evolve» (+1). · the question and its options parsed, with trees and pragmatics

Test 8 · right ✓

What is the air pocket at the wide end of an egg for?

1. Storing the chick's food and water for later, until it is ready to hatch — no support
2. Nothing, it is just empty — no support
3. The chick's first breath before it breaks the shell — ← Mova's choice · ✓ the right answer · score 4
4. Keeping the egg from sinking in the nest — no support

Why: It took the question to ask a circumstance (with what, when, how). It chose option 3 with score 4, the only option with support. Its support: lesson 33, line 9: «An egg has an air pocket at the wide end, white for water and cushioning, a yolk for food, and thousands of tiny holes in the shell that let air in; before it…», reached through the same lesson line as the sentence the question matched. What matched: the same action «break» (+4); the same thing acted on «shell» (+2). Against it: a different doer (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Test 9 · right ✓

In a game, birds have solid heavy bones to make them tough. Why would real flying birds be worse off?

1. They would not be able to see — no support
2. Birds would grow too tall — no support
3. Solid bones would break much more easily in the air — no support
4. Heavy bones would make flying cost far more energy — ← Mova's choice · ✓ the right answer · score -1

Why: It took the question to ask why something happens (its cause). It chose option 4 with score -1, the only option with support. Its support: lesson 15, line 10: «Howler monkeys have a big hollow bone in the throat that makes their call heard about 5 kilometres away, so troops know where the others are without fighting.», reached through the option's own match among the sentences about the question's things. What matched: the same action «make» (+1). Against it: a different thing acted on (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Test 10 · right ✓

A barn swallow ringed in a Devon barn is found in South Africa in winter. What does this show?

1. Swallows migrate thousands of kilometres for winter — ← Mova's choice · ✓ the right answer · score 7
2. Swallows live in Africa all year — score 5
3. Someone carried it there by plane — no support
4. It was blown off course in a big storm — no support

Why: It took the question to ask what it is done to. It chose option 1 with score 7, against 5 for the next best. Its support: lesson 33, line 15: «Swallows from Britain fly about 10,000 km to South Africa for the winter, because a British winter has almost no flying insects for them to eat, and South Afri…», reached through the option's own match among the sentences about the question's things. What matched: the same doer «swallows» (+4); the same property (+3). · the question and its options parsed, with trees and pragmatics

Test 11 · right ✓

Why do birds sing loudest at dawn?

1. The air is still and quiet, so songs carry far — ← Mova's choice · ✓ the right answer · score 10
2. The sun makes their throats warm — no support
3. Birds can only see at dawn — score 0
4. They are complaining loudly that they are hungry after the long night — no support

Why: It took the question to ask why something happens (its cause). It chose option 1 with score 10, against 0 for the next best. Its support: lesson 33, line 18: «Most birdsong is sung by males to claim a territory, but European robins of both sexes sing in winter to defend their patch; birds sing loudest at dawn, when t…», reached through the same lesson line as the sentence the question matched. What matched: the same action «carry» (+4); the same doer «songs» (+4); the same property (+2). · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · right ✓

Identify the principal function of the hooked barbules of a feather.

1. To interlock the barbs into a continuous surface — ← Mova's choice · ✓ the right answer · no support
2. To anchor the feather within the skin — no support
3. To store oil for waterproofing — no support
4. To sense vibrations of the air during flight — 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

Exam question 2 · formal language · wrong ✗

Which of the following statements most accurately characterises the formation of geese in flight?

1. The formation serves solely for display — ← Mova's choice · no support
2. The leading bird bears no additional burden — no support
3. Each bird benefits from rising air generated by the wingtip of the bird ahead — ✓ the right answer · no support
4. The formation is maintained by vocal command alone, issued by the eldest goose of the flock — 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 ✗

Ascertain the role of grit retained within the avian gizzard.

1. The neutralisation of stomach acid — ← Mova's choice · no support
2. The mechanical grinding of food — ✓ the right answer · no support
3. The ballasting of the bird in flight — no support
4. The production of eggshell material — 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 ✗

It is given that eggs are produced by hens maintained without a cockerel. Determine the consequence.

1. The eggs hatch more rapidly — ← Mova's choice · score 8
2. The eggs are incapable of hatching — ✓ the right answer · no support
3. The eggs yield only male chicks — no support
4. The eggs possess no yolk — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 8, the only option with support. Its support: lesson 33, line 10: «Supermarket eggs never hatch because the hens live without a cockerel, and a hen lays about one egg a day.», reached through the same lesson line as the sentence the question matched. What matched: the same action «hatch» (+5); the same doer «supermarket eggs» (+5). Against it: one says «not», the other does not (counts against) (-2). 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/biology/33-birds-feathers-wings-eggs-and-flight/