The aquarium: the shark tunnel and the rays

Tests: 5 of 12 right · Exam: 3 of 4 right · Kind: plain · Understood: 10 of 16 · Run: 2026-10-18, commit f3c23ea72

Lesson 91 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 ✗

mate says the tunnel glass could crack any second if a shark headbutts it lol. true?

1. Yes, that is why the sharks are kept hungry — ← Mova's choice · no support
2. Yes, sharks often break the tunnels and the water floods in — no support
3. No, the acrylic is many centimetres thick and very strong — ✓ the right answer · no support
4. No, because the tunnel is made of steel — 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 2 · wrong ✗

What would most likely happen if the keepers stopped feeding the tank sharks?

1. Nothing, sharks never get hungry — ← Mova's choice · score 4
2. The hungry sharks would start hunting their tankmates — ✓ the right answer · score 3
3. The other fish would eat the sharks — score 3
4. The sharks would eat seaweed instead — score 1

Why: It took the question to ask what happens next. It chose option 1 with score 4, against 3 for the next best. Its support: lesson 91, line 2: «The sharks swim past the smaller fish without snapping at them, because the keepers feed them full meals from a long pole and a full shark is not hunting.», reached through what followed the sentence the question matched. What matched: the same doer «sharks» (+4). The right option, 2, scored 3. · the question and its options parsed, with trees and pragmatics

Test 3 · wrong ✗

Your cousin says a shark with that many teeth must be a killer. What is the best reply?

1. Yes, all sharks with long teeth attack people — ← Mova's choice · score 3
2. Teeth alone do not show danger; sand tigers are calm — ✓ the right answer · no support
3. No, sand tigers have no teeth at all — no support
4. Yes, the more teeth a shark has, the more dangerous it is — score 3

Why: It took the question to ask what it is done to. 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 28, line 8: «Great white sharks often attack seals from below and can burst right out of the water; they grow to about 6 metres and can live over 70 years.», reached through the option's own match among the sentences about the question's things. What matched: the same action «attack» (+2); the same doer «great white sharks» (+2). Against it: a different thing acted on (counts against) (-1). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 4 · right ✓

After watching Jaws, Ben thinks the sea is full of sharks hunting swimmers. What is the truth?

1. Sharks kill fewer than about ten people a year — ← Mova's choice · ✓ the right answer · score 7
2. Sharks follow boats to find people — score 2
3. Every beach has a great white nearby — no support
4. Sharks kill thousands of swimmers every single year — score 7

Why: It took the question to ask which statement is true. 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 28, line 4: «Films like Jaws show sharks hunting people; in truth, sharks kill only a handful of people a year, usually by mistaking a swimmer for a seal, while people kill…», reached through the same lesson line as the sentence the question matched. What matched: the same action «kill» (+4); the same property (+3). · the question and its options parsed, with trees and pragmatics

Test 5 · right ✓

In Finding Nemo, Bruce the great white shark is in a club where sharks promise not to eat fish. What is true of real great whites?

1. They never eat fish at all, only tiny drifting plankton and krill — score 1
2. They live in small groups in one reef — no support
3. They do eat fish and seals, and they roam huge distances — ← Mova's choice · ✓ the right answer · score 4
4. They eat only seaweed and shellfish — score 3

Why: It took the question to ask which statement is true. It chose option 3 with score 4, against 3 for the next best. Its support: lesson 7, line 10: «The leopard seal, about 3.5 metres long, eats krill, fish, penguins and other seals, and its back teeth lock together like a sieve to strain krill.», reached through the remembered sentence the question matched. What matched: the same thing acted on «krill» (+5); the same action «eat» (+2). Against it: a different doer (counts against) (-3). · the question and its options parsed, with trees and pragmatics

Test 6 · right ✓

A ray in the touch pool has no barb on its tail. Why?

1. Keepers trimmed it safely so visitors cannot be stung — ← Mova's choice · ✓ the right answer · score 3
2. Rays are born without barbs — no support
3. It used the barb to spear fish and snapped it off on a rock — score 2
4. The barb only grows in the wild ocean — no support

Why: It took the question to ask why something happens (its cause). It chose option 1 with score 3, against 2 for the next best. Its support: lesson 91, line 12: «In touch pools the rays' barbs are safely trimmed, and visitors stroke them gently with two fingers so the animals are not hurt.», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «barbs» (+2); the same action «trim» (+1). · the question and its options parsed, with trees and pragmatics

Test 7 · wrong ✗

Why would a flat body help a ray?

1. It can swim faster than any shark in the whole ocean — ← Mova's choice · no support
2. It can climb up rocks — no support
3. It can hide in sand and glide along the sea floor — ✓ the right answer · no support
4. It can float on the surface to sunbathe — 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 ✓

3 sawfish and 2 mantas cruise past, no wait, 4 mantas. how many tails is that

1. 7 — ← Mova's choice · ✓ the right answer · no support
2. 9 — no support
3. 5 — no support
4. 14 — 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 9 · wrong ✗

A shark has five gill slits on each side. How many gill slits does it have in all?

1. 15 — ← Mova's choice · no support
2. 8 — no support
3. 10 — ✓ the right answer · no support
4. 5 — 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 10 · wrong ✗

Stroke a shark from nose to tail and then from tail to nose. What do you feel?

1. Slimy both ways like a frog — ← Mova's choice · score 1
2. Smooth both ways, just like stroking a wet dolphin — score -7
3. Smooth one way and rough like sandpaper the other — ✓ the right answer · score 1
4. Spiky both ways like a hedgehog — score 1

Why: It took the question to ask what it is done to. It chose option 1 with score 1, tied with another option at 1 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 91, line 18: «Shark skin is covered in tiny tooth-like scales called denticles, which feel smooth one way and like sandpaper the other and help water slip past.», reached through the remembered sentence the question matched. What matched: the same action «feel» (+5); it fills the role the question asks for (+1). Against it: the same thing acted on «smooth one way» (-1); a different doer (counts against) (-4). The right option, 3, scored 1. · the question and its options parsed, with trees and pragmatics

Test 11 · wrong ✗

Which is the biggest fish in the world?

1. The giant manta ray — no support
2. The whale shark — ✓ the right answer · no support
3. The great blue whale — no support
4. The great white shark — ← Mova's choice · score 4

Why: It took the question to ask which statement is true. It chose option 4 with score 4, the only option with support. Its support: lesson 91, line 9: «Great white sharks, the sharks of Jaws, hunt fish and seals and are rarely kept in aquariums because they swim huge distances and many stopped eating or died i…», reached through the option's own match among the sentences about the question's things. What matched: the same property (+3); the same doer «great white sharks» (+1). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 12 · right ✓

Why do some of the biggest sea animals eat some of the smallest food?

1. Plankton is everywhere, so filtering it feeds a huge body — ← Mova's choice · ✓ the right answer · no support
2. Small food is easier to see in the dark — no support
3. They are too slow to catch anything else — no support
4. Their teeth are too weak for bigger food — 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 · wrong ✗

Identify the principal reason for which sharks maintained within aquarium exhibits refrain from predation upon their tankmates.

1. They are separated from all other fish by partitions — no support
2. They are provided with regular and sufficient meals by the keepers — ✓ the right answer · score 1
3. They are physically incapable of consuming fish of any appreciable size — ← Mova's choice · score 4
4. Their tankmates are invariably venomous — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 4, against 1 for the next best. Its support: lesson 91, line 9: «Great white sharks, the sharks of Jaws, hunt fish and seals and are rarely kept in aquariums because they swim huge distances and many stopped eating or died i…», reached through the same lesson line as the sentence the question matched. What matched: the same doer «great white sharks» (+4); the same thing acted on «fish» (+1). Against it: a different action (counts against) (-1). The right option, 2, scored 1. · 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 relationship between sharks and rays?

1. Rays are juvenile sharks which have not yet attained their adult form and fins — score 5
2. Rays are marine mammals resembling sharks — no support
3. Rays are flattened relatives of sharks, both possessing cartilaginous skeletons — ← Mova's choice · ✓ the right answer · score 7
4. Rays are bony fish unrelated to sharks — score 5

Why: It took the question to ask who or what does it. It chose option 3 with score 7, against 5 for the next best. Its support: lesson 91, line 11: «Rays are flat relatives of sharks with cartilage skeletons; they hide in sand and eat shellfish and worms, and a stingray's barb on its tail is only for defenc…», reached through the option's own match among the sentences about the question's things. What matched: the same circumstance (+2); it fills the role the question asks for (+2); the same doer «rays» (+1); the same thing acted on «flat relatives» (+1). · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · right ✓

Select the response consistent with the established facts concerning the whale shark.

1. It is the largest fish and subsists upon plankton and small fish — ← Mova's choice · ✓ the right answer · score 7
2. It is a mammal that respires by means of lungs — no support
3. It is a modest fish of under two metres — score 7
4. It is a whale which hunts other sharks throughout the open oceans — score 6

Why: It took the question to ask which statement is true. 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 91, line 19: «The whale shark is the biggest fish of all, up to about 18 metres long, and it filters plankton and small fish; it is a shark, not a whale, because it breathes…», reached through the same lesson line as the sentence the question matched. What matched: the same doer «fish» (+4); the same circumstance (+3). · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · right ✓

It is given that the sawfish is designated critically endangered. Ascertain the principal cause thereof.

1. Entanglement of its saw in fishing nets — ← Mova's choice · ✓ the right answer · no support
2. Predation upon it by manta rays — no support
3. Insufficiency of plankton in its waters — no support
4. Excessive warmth of the ocean surface — 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

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/biology/91-the-aquarium-the-shark-tunnel-and-the-rays/