Echolocation in the sea and in people: dolphins, whales, swiftlets and clicking humans

Tests: 4 of 11 right · Exam: 2 of 4 right · Kind: ★★ · Understood: 11 of 15 · Run: 2026-10-18, commit f3c23ea72

Lesson 230 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 ✗

In a cartoon a fish chats in a squeaky voice. What do real fish do?

1. They cannot talk, but many grunt, click or drum — ✓ the right answer · score 8
2. They stay silent all their lives — no support
3. They sing like birds — no support
4. They talk quietly to each other in real words, like us — ← Mova's choice · score 11

Why: It took the question to ask what is done. It chose option 4 with score 11, against 8 for the next best. Its support: lesson 160, line 12: «Elephantnose fish make weak electricity to sense their surroundings and talk to each other in dark, muddy water.», reached through the option's own match among the sentences about the question's things. What matched: it fills the role the question asks for (+5); the same action «talk» (+4); the same circumstance (+2). The right option, 1, scored 8. · the question and its options parsed, with trees and pragmatics

Test 2 · ★★ · right ✓

«a blind guy on the news rides a BIKE?? how» What is the best answer?

1. He clicks his tongue and reads the echoes, like a bat — ← Mova's choice · ✓ the right answer · no support
2. He can secretly see — no support
3. He uses a map in his head only, and remembers every bump in the road — no support
4. The bike drives itself — 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 ✗

Try it: shut your eyes and walk slowly towards a wall while humming. What may you notice?

1. Nothing at all, ever — no support
2. Your eyes see through your eyelids — ← Mova's choice · score 9
3. You can often hear when the wall is close — ✓ the right answer · no support
4. The wall hums back a tune — no support

Why: It took the question to ask what it is done to. It chose option 2 with score 9, the only option with support. Its support: lesson 106, line 11: «Reindeer eyes change from golden in summer to blue in winter, which helps them see in the long dark winter.», reached through the option's own match among the sentences about the question's things. What matched: the same action «see» (+5); the same doer «eyes» (+4). The right option, 3, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 4 · ★★ · right ✓

What would happen if a dolphin's lower jaw could not pass sound?

1. It would hear its echoes badly and find food harder — ← Mova's choice · ✓ the right answer · score 7
2. It could no longer breathe — no support
3. Nothing, because dolphins hear only through their tails — score 3
4. It would swim backwards — no support

Why: It took the question to ask what happens next. It chose option 1 with score 7, against 3 for the next best. Its support: lesson 229, line 10: «Some tiger moths click back at bats to jam their echoes or warn that they taste nasty, and some moths can hear bats and dive away; the fluffy scales on some mo…», reached through what followed the sentence the question matched. What matched: the same action «hear» (+4); the same thing acted on «less echo» (+4). Against it: a different doer (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 5 · ★★ · wrong ✗

A blue whale and a sperm whale are side by side in a book. Which one hunts with echoes?

1. Neither of them — no support
2. The blue whale, a baleen whale — ← Mova's choice · score 9
3. The sperm whale, a toothed whale — ✓ the right answer · score 9
4. Both of them — no support

Why: It took the question to ask who or what does it. It chose option 2 with score 9, tied with another option at 9 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 230, line 7: «Sperm whales hunt squid more than a kilometre down in total darkness with clicks that are among the loudest sounds any animal makes.», reached through the option's own match among the sentences about the question's things. What matched: it fills the role the question asks for (+4); the same doer «sperm whales» (+3); the same action «hunt» (+2). The right option, 3, scored 9. · the question and its options parsed, with trees and pragmatics

Test 6 · ★★ · right ✓

«why don't blue whales need clicks, they're massive» What is the best answer?

1. They gulp huge mouthfuls of tiny krill, not single fast prey — ← Mova's choice · ✓ the right answer · score 6
2. They eat only plants — score 6
3. They see perfectly in the dark sea, so they never need any echoes — score 6
4. They are too lazy to click — score 6

Why: It took the question to ask why something happens (its cause). 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 200, line 14: «Rabbits are social animals that need lots of space to run and a rabbit friend; pet rabbits can live eight to twelve years.», reached through the cause of the sentence the question matched. What matched: the same doer «social animals» (+3); a different action (counts against) (+3). · the question and its options parsed, with trees and pragmatics

Test 7 · ★★ · wrong ✗

After 11 September 2001 there were fewer ships for a few days. What did scientists find in right whales?

1. More stress than before — ← Mova's choice · score 10
2. Calmer stress levels — ✓ the right answer · score 10
3. They swam into the empty ports — no support
4. They forgot their songs — score 4

Why: It took the question to ask what it is done to. It chose option 1 with score 10, tied with another option at 10 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 190, line 3: «Others were hiding in plain sight: the olinguito was found by a scientist looking at old skins in a museum drawer, like finding a new toy at the bottom of the…», reached through the option's own match among the sentences about the question's things. What matched: the same action «find» (+5); the same doer «scientist» (+4); a different thing acted on (counts against) (+1). The right option, 2, scored 10. · the question and its options parsed, with trees and pragmatics

Test 8 · ★★ · right ✓

«that dolphin's staring at my mum, creepy» What might really be going on?

1. Dolphins cannot see people — score 6
2. Dolphins stare to hypnotise people — score 2
3. It may be clicking at her, and echoes pass a little way into her body — ← Mova's choice · ✓ the right answer · score 10
4. It wants to bite her — score 2

Why: It took the question to ask who or what does it. It chose option 3 with score 10, against 6 for the next best. Its support: lesson 230, line 16: «Some people say dolphins can tell if a woman is going to have a baby by echoes; dolphin clicks do pass a little way into a body, but this has not been properly…», reached through the same lesson line as the sentence the question matched. What matched: the same action «pass» (+5); the same thing acted on «little way» (+2); the same place «body» (+2); a different doer (counts against) (+1). · the question and its options parsed, with trees and pragmatics

Test 9 · ★★ · wrong ✗

A friend says people invented echolocation with sonar. What is wrong with that?

1. Nothing, only people use it — ← Mova's choice · score 5
2. Bats and dolphins used it for tens of millions of years before us — ✓ the right answer · score 2
3. Sonar was copied from fish that talk to each other on the coral reefs — score 3
4. Sonar uses light, not sound — score 2

Why: It took the question to ask which statement is true. It chose option 1 with score 5, against 3 for the next best. Its support: lesson 208, line 14: «Horses are flight animals that react first and think later, so they may snort and jump at a plastic bag, and calm, patient riders help them get used to scary t…», reached through the option's own match among the sentences about the question's things. What matched: the same doer «people» (+3); the same action «use» (+2). The right option, 2, scored 2. · the question and its options parsed, with trees and pragmatics

Test 10 · ★★ · wrong ✗

Count them: 3 dolphins and 2 orcas swim past. How many blowholes, and how many tails?

1. 3 blowholes and 5 tails — ← Mova's choice · no support
2. 10 blowholes and 5 tails — no support
3. 5 blowholes and 10 tails — no support
4. 5 blowholes and 5 tails — ✓ 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 11 · ★★ · wrong ✗

A coral reef is recorded at night. What will the recording sound like?

1. Totally silent — ← Mova's choice · no support
2. Like birds singing — no support
3. Noisy with crackles from shrimps and grunts from fish — ✓ the right answer · no support
4. Only like waves breaking far away on the beach — 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 1 · formal language · right ✓

Identify the anatomical structure through which the returning echoes are conveyed to the ear of a dolphin.

1. The blowhole — no support
2. The lower jaw — ← Mova's choice · ✓ the right answer · score 7
3. The tail fluke — no support
4. The dorsal fin — 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 230, line 5: «Dolphins echolocate with clicks made in their nose passages and focused by the fatty «melon» in the forehead; echoes return through the lower jaw to the ears.», reached through the option's own match among the sentences about the question's things. What matched: the same place «lower jaw» (+4); the same property (+3). · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · right ✓

Which of the following statements most accurately characterises the capacity for echolocation amongst whales?

1. It is possessed by toothed whales but apparently not by baleen whales — ← Mova's choice · ✓ the right answer · score 3
2. It is possessed by baleen whales alone — score 3
3. It is possessed by no whale whatsoever — score 3
4. It is possessed by all whales without exception — score 3

Why: It took the question to ask who or what does it. It chose option 1 with score 3, tied with another option at 3 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 195, line 6: «A clicker makes a short sharp click that marks the exact moment the dog did the right thing, and the treat follows; zoos use clicker training so animals calmly…», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+2); the same doer «animals» (+1). · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · wrong ✗

Select the response consistent with the established facts concerning human echolocation.

1. No human being is capable of perceiving echoes — ← Mova's choice · no support
2. Certain blind persons perceive their surroundings by means of tongue clicks and their echoes — ✓ the right answer · no support
3. It is possible only beneath the surface of water — no support
4. Human echolocation requires an implanted device — 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 ✗

Ascertain the principal reason for which sound is preferred to light for the detection of objects in the deep sea.

1. Light is rapidly extinguished in water, whereas sound is propagated far and swiftly — ✓ the right answer · no support
2. Water amplifies light but absorbs sound, thereby rendering sound of little use at great depth — ← Mova's choice · score 5
3. Light travels more slowly in water than sound — score 5
4. Sound is visible to marine animals — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 5, tied with another option at 5 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 8, line 2: «When you snorkel the water looks blue because water soaks up red light first and blue light last, so the deeper you go the bluer and darker it gets, until ther…», reached through the option's own match among the sentences about the question's things. What matched: the same doer «water» (+3); the same action «soak up» (+2). The right option, 1, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

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