--- title: Birds: feathers, nests and flight — how Mova does on the tests · World description: Lesson 73 of the world course of Mova's primary school: 10 of 13 tests right, exam 1 of 4, every question with the options, the student's choice, the right answer and why it chose. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/school-run/world/73-birds-feathers-nests-flight/) [home](https://md.mova.elamur.ai/free/en/) / [at school](https://md.mova.elamur.ai/free/en/school-run/) / [World](https://md.mova.elamur.ai/free/en/school-run/world/) / 73 # Birds: feathers, nests and flight **Tests:** 10 of 13 right · **Exam:** 1 of 4 right · **Kind:** ★ · **Understood:** 14 of 17 · **Run:** 2026-10-18, commit `f3c23ea72` Lesson 73 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](https://md.mova.elamur.ai/free/en/corpora/school/world/73-birds-feathers-nests-flight/). Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: [the lesson's questions in the corpora](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/). ### Test 1 · ★ · wrong ✗ {#t1} A duck dives under the water and comes up with dry feathers underneath. Why? - **1.** Ducks dive too briefly to get wet — no support - **2.** The water is too cold to wet feathers — **← Mova's choice** · score 5 - **3.** Ducks have no feathers at all under their wings and belly — no support - **4.** Its feathers are oiled and waterproof from preening — **✓ the right answer** · no support **Why:** It took the question to ask why something happens (its cause). It chose option 2 with score 5, the only option with support. Its support: lesson 50, line 3: «High in the mountains it is colder, even though you are a little closer to the Sun: sunlight warms the ground, the ground warms the air, and air that rises exp…», reached through the option's own match among the sentences about the question's things. What matched: the same light verb (be, have, do, get, go) (+3); the same doer «water» (+1); the same property (+1). The right option, 4, found no support in what it remembers. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t1/) ### Test 2 · ★ · wrong ✗ {#t2} A bird has a long, thin, curved beak. What does it most likely eat? - **1.** Big hard seeds and nuts from trees — **← Mova's choice** · score 7 - **2.** Little fish sifted from the mud — no support - **3.** Meat from other small animals — score 7 - **4.** Nectar from deep flowers — **✓ the right answer** · score 7 **Why:** It took the question to ask what it is done to. 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 73, line 4: «A bird's beak shows what it eats: a hooked beak tears meat, a short thick beak cracks seeds, a long thin beak reaches nectar in flowers and a flat beak sifts f…», 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 thing acted on «seeds» (+3). The right option, 4, scored 7. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t2/) ### Test 3 · ★ · right ✓ {#t3} A coat filled with feathers is very warm. Which feathers are used and why? - **1.** Tail feathers, because they are long — score 2 - **2.** Any feathers, because all feathers are hot — no support - **3.** Down, because it traps a lot of air — **← Mova's choice** · **✓ the right answer** · score 4 - **4.** Flight feathers, because they are stiff — score 1 **Why:** It took the question to ask what it is done to. It chose option 3 with score 4, against 2 for the next best. Its support: lesson 73, line 7: «Down feathers trap air and keep a bird warm.», reached through the option's own match among the sentences about the question's things. What matched: the same action «trap» (+4); the same property (+1). Against it: a different thing acted on (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t3/) ### Test 4 · ★ · right ✓ {#t4} A bird with very broad wings circles high without flapping on a sunny day. How does it stay up? - **1.** It rides on warm air rising from the ground — **← Mova's choice** · **✓ the right answer** · no support - **2.** It is lighter than the air around it — no support - **3.** It is pulled up by the Sun — no support - **4.** Its hollow bones are filled with a light gas like a balloon — 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](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t4/) ### Test 5 · ★ · right ✓ {#t5} If a bird's bones were solid and heavy like ours, what would happen? - **1.** It would stay warmer in winter — no support - **2.** It would need no wings at all — no support - **3.** Flying would be much harder — **← Mova's choice** · **✓ the right answer** · score 3 - **4.** It would fly faster and higher — no support **Why:** It took the question to ask what happens next. It chose option 3 with score 3, the only option with support. Its support: lesson 71, line 18: «Astronauts' muscles and bones weaken in space, so they exercise about two hours every day.», reached through what followed the sentence the question matched. What matched: the same doer «muscles» (+3). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t5/) ### Test 6 · ★ · right ✓ {#t6} A small bird is busy feeding a chick much bigger than itself in its nest. What might explain this? - **1.** The chick grew big from extra warmth — score 5 - **2.** The small bird found the chick on the ground — score 4 - **3.** The chick is the small bird's own baby — no support - **4.** A cuckoo laid its egg in that nest — **← Mova's choice** · **✓ the right answer** · score 9 **Why:** It took the question to ask what it is done to. It chose option 4 with score 9, against 5 for the next best. Its support: lesson 24, line 9: «Birds have feathers, a beak and lay eggs with hard shells.», reached through the option's own match among the sentences about the question's things. What matched: the same action «lay» (+4); it fills the role the question asks for (+3); the same thing acted on «eggs» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t6/) ### Test 7 · ★ · wrong ✗ {#t7} Why do paper aeroplane wings and real plane wings work a bit like a bird's wing? - **1.** Air flowing past the wings pushes them up — **✓ the right answer** · score 3 - **2.** They are lighter than air — **← Mova's choice** · score 5 - **3.** They flap up and down just like a bird's wings — no support - **4.** They are made of feathers — no support **Why:** It took the question to ask why something happens (its cause). It chose option 2 with score 5, against 3 for the next best. Its support: lesson 71, line 1: «A rocket works like a balloon let go: it throws hot gas out of its tail very hard, and the gas pushes the rocket the other way. It needs no air to push against…», reached through the cause of the sentence the question matched. What matched: the same circumstance (+4); a different doer (counts against) (+1). The right option, 1, scored 3. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t7/) ### Test 8 · ★ · right ✓ {#t8} A chicken swallows small stones. Why? - **1.** The stones help its gizzard grind food — **← Mova's choice** · **✓ the right answer** · score 10 - **2.** The stones keep its feathers clean — no support - **3.** The stones clean its beak — no support - **4.** The stones make it heavier in wind — no support **Why:** It took the question to ask why something happens (its cause). It chose option 1 with score 10, the only option with support. Its support: lesson 35, line 1: «Teeth cut, tear and grind food so it can be swallowed and digested.», reached through the cause of the sentence the question matched. What matched: the same action «grind» (+5); the same thing acted on «food» (+4); a different doer (counts against) (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t8/) ### Test 9 · ★ · right ✓ {#t9} Which is true about birds and dinosaurs? - **1.** Dinosaurs came from birds — no support - **2.** Birds are living descendants of dinosaurs — **← Mova's choice** · **✓ the right answer** · score 7 - **3.** Birds and dinosaurs were never related — no support - **4.** All dinosaurs could fly, just like the birds today — no support **Why:** It took the question to ask which statement is true. It chose option 2 with score 7, the only option with support. Its support: lesson 73, line 18: «Birds are living descendants of dinosaurs.», reached through the remembered sentence the question matched. What matched: the same circumstance (+4); the same doer «birds» (+2); the same thing acted on «living descendants» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t9/) ### Test 10 · ★ · right ✓ {#t10} why do birds keep picking at their feathers all the time - **1.** They are pulling out feathers to build nests — score 3 - **2.** They preen to keep their feathers clean, tidy and waterproof — **← Mova's choice** · **✓ the right answer** · score 9 - **3.** They are scratching bites from other birds — no support - **4.** They are looking for food hidden in them — no support **Why:** It took the question to ask which statement is true. It chose option 2 with score 9, against 3 for the next best. Its support: lesson 73, line 14: «Birds preen to keep their feathers clean, tidy and waterproof.», reached through a sentence linked to the one the question matched. What matched: the same action «preen» (+4); its «because» matches the remembered cause (+3); the same doer «birds» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t10/) ### Test 11 · ★ · right ✓ {#t11} how do birds chew if they got no teeth - **1.** A muscly part of the stomach, the gizzard, grinds the food — **← Mova's choice** · **✓ the right answer** · score 8 - **2.** They chew with hard ridges on their tongue — no support - **3.** They only eat soft food like nectar and worms that needs no chewing — score 3 - **4.** Their beaks have tiny teeth too small to see — no support **Why:** It took the question to ask which statement is true. It chose option 1 with score 8, against 3 for the next best. Its support: lesson 73, line 11: «Birds have no teeth; a muscly part of the stomach called the gizzard grinds their food, often with swallowed grit.», reached through the same lesson line as the sentence the question matched. What matched: the same doer «muscly part» (+4); the same action «grind» (+3); the same thing acted on «food» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t11/) ### Test 12 · ★ · right ✓ {#t12} Ava says birds' bones are solid and heavy so they're strong. true? - **1.** No, many bird bones are hollow, which makes them light — **← Mova's choice** · **✓ the right answer** · score 2 - **2.** Yes, heavy bones help birds fly steadily — no support - **3.** No, birds have no bones, only muscle — no support - **4.** Yes, but only in birds that cannot fly — 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 38, line 3: «Exercise makes muscles stronger, including the heart, and makes bones thicker and stronger. About an hour of active play a day is good for children.», reached through the option's own match among the sentences about the question's things. What matched: the same action «make» (+1); the same thing acted on «bones» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t12/) ### Test 13 · ★ · right ✓ {#t13} my sister reckons birds have nothing to do with dinosaurs. right? - **1.** No, birds are a kind of flying reptile — score 3 - **2.** Yes, birds came long before the dinosaurs — score 6 - **3.** Yes, birds are related only to bats — no support - **4.** No, birds are living descendants of dinosaurs — **← Mova's choice** · **✓ the right answer** · score 7 **Why:** It took the question to ask which statement is true. It chose option 4 with score 7, against 6 for the next best. Its support: lesson 73, line 18: «Birds are living descendants of dinosaurs.», reached through the remembered sentence the question matched. What matched: the same circumstance (+4); the same doer «birds» (+2); the same thing acted on «living descendants» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/t13/) ### Exam question 1 · formal language · wrong ✗ {#e1} Which of the following statements most accurately characterises the material of which feathers are composed? - **1.** Chitin, the same material as insect shells — **← Mova's choice** · no support - **2.** Bone, the same hard material as the rest of the skeleton — no support - **3.** Keratin, the same material as hair and nails — **✓ the right answer** · no support - **4.** Cartilage, the same material as the ears — 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](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/e1/) ### Exam question 2 · formal language · wrong ✗ {#e2} Identify the principal reason for which many of a bird's bones are hollow. - **1.** It permits the bird to float upon water — **← Mova's choice** · no support - **2.** It renders the bird warmer in winter — no support - **3.** It renders the bird light for flight — **✓ the right answer** · no support - **4.** It permits the bird to store water — 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](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/e2/) ### Exam question 3 · formal language · wrong ✗ {#e3} Ascertain the manner in which a bird grinds its food in the absence of teeth. - **1.** By the claws, which tear the food into dust — **← Mova's choice** · score 2 - **2.** By the beak, which chews the food thoroughly — score 2 - **3.** By the gizzard, a muscly part of the stomach, often with grit — **✓ the right answer** · no support - **4.** By the tongue, pressed against the palate — no support **Why:** It took the question to ask which statement is true. It chose option 1 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 35, line 10: «Canines are pointed teeth for tearing food.», reached through the option's own match among the sentences about the question's things. What matched: the same action «tear» (+1); the same thing acted on «food» (+1). The right option, 3, found no support in what it remembers. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/e3/) ### Exam question 4 · formal language · right ✓ {#e4} Select the response that is consistent with the established facts concerning the cuckoo. - **1.** It lays its eggs in other birds' nests to be raised by them — **← Mova's choice** · **✓ the right answer** · score 3 - **2.** It carries its eggs in a pouch until they hatch — no support - **3.** It builds nests of mud beneath the eaves of houses — no support - **4.** It buries its eggs in warm sand — no support **Why:** It took the question to ask which statement is true. It chose option 1 with score 3, the only option with support. Its support: lesson 73, line 17: «A cuckoo lays its eggs in other birds' nests and lets them raise its chicks.», reached through the option's own match among the sentences about the question's things. What matched: the same place «nests» (+2); the same action «lay» (+1); the same thing acted on «eggs» (+1). Against it: a different doer (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/world/73-birds-feathers-nests-flight/e4/) - ← previous: [72. Insects and spiders](https://md.mova.elamur.ai/free/en/school-run/world/72-insects-and-spiders/) - next →: [74. Fish, frogs and reptiles](https://md.mova.elamur.ai/free/en/school-run/world/74-fish-frogs-reptiles/) - ↑ back to [World](https://md.mova.elamur.ai/free/en/school-run/world/)