---
title: Unusual pets: stick insects, giant snails, ant farms and hermit crabs — how Mova does on the tests · Biology
description: Lesson 330 of the biology course of Mova's primary school: 9 of 12 tests right, exam 3 of 4, every question with the options, the student's choice, the right answer and why it chose.
---

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# Unusual pets: stick insects, giant snails, ant farms and hermit crabs

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**Tests:** 9 of 12 right · **Exam:** 3 of 4 right · **Kind:** ★★★ · **Understood:** 11 of 16 · **Run:** 2026-10-18, commit `f3c23ea72`

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Lesson 330 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](https://md.mova.elamur.ai/free/en/corpora/school/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/).

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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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/).

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### Test 1 · ★★★ · right ✓ {#t1}

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Count them: 5 stick insects sit on a twig. How many legs in all?

- **1.** 30 — **← Mova's choice** · **✓ the right answer** · no support
- **2.** 40 — no support
- **3.** 20 — no support
- **4.** 25 — no support

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**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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t1/)

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### Test 2 · ★★★ · wrong ✗ {#t2}

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Count them: 3 hermit crabs in a tank. How many legs really, and how many are easy to see?

- **1.** 18 legs, with 18 easy to see — **← Mova's choice** · no support
- **2.** 30 legs, with 30 easy to see — no support
- **3.** 24 legs, with 18 easy to see — no support
- **4.** 30 legs, with 18 easy to see — **✓ the right answer** · no support

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**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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t2/)

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### Test 3 · ★★★ · right ✓ {#t3}

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In A Bug's Life the ants walk on two legs and use two arms like people. Count them: how many legs does each real ant have, and how many would 4 real ants have?

- **1.** 6 each, so 24 — **← Mova's choice** · **✓ the right answer** · no support
- **2.** 8 each, so 32 in all — no support
- **3.** 4 each, so 16 in all — no support
- **4.** Only 2 each, so 8 — no support

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**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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t3/)

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### Test 4 · ★★★ · right ✓ {#t4}

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In SpongeBob, Mr. Krabs walks on two thin legs. How many legs does a real crab of his kind have, counting the claws?

- **1.** 10 — **← Mova's choice** · **✓ the right answer** · no support
- **2.** 12 — no support
- **3.** 8 — no support
- **4.** 6 — no support

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**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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t4/)

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### Test 5 · ★★★ · right ✓ {#t5}

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«me mate's gonna let his snails go in the park, they'll be happier» What is the best answer?

- **1.** Only if he lets them go at night — score 3
- **2.** Great, snails love parks — no support
- **3.** Released pets can die or become pests; take them to a rescue or pet shop — **← Mova's choice** · **✓ the right answer** · score 12
- **4.** Fine, pet snails always do much better out in the wild than in any tank — score 2

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**Why:** It took the question to ask what it is done to. It chose option 3 with score 12, against 3 for the next best. Its support: lesson 330, line 4: «These pets come with one rule: never let them go outside. Released pets can die or become pests, and many pests around the world began as someone's unwanted pe…», reached through the same lesson line as the sentence the question matched. What matched: the same action «become» (+6); the same doer «released pets» (+3); it fills the role the question asks for (+2); the same thing acted on «pests» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t5/)

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### Test 6 · ★★★ · right ✓ {#t6}

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«got ants from the shop, no queen, they'll be fine» What will happen?

- **1.** They will choose a new queen from a worker in a day — score 0
- **2.** Without a queen laying eggs, the colony will die out in a few months — **← Mova's choice** · **✓ the right answer** · score 7
- **3.** They will live for ever without one — score 7
- **4.** The biggest ant will lay all the eggs — score 3

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**Why:** It took the question to ask what happens next. It chose option 2 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 330, line 10: «An ant colony needs a queen to lay eggs or it slowly dies out, and ants from shops without a queen last only a few months.», reached through what followed the sentence the question matched. What matched: the same action «die out» (+6); the same doer «colony» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t6/)

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### Test 7 · ★★★ · right ✓ {#t7}

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Scientists dab the «dead ant» smell on a living ant. What happens?

- **1.** Nothing, because ants judge death by looking, not by smell — score 5
- **2.** Its sisters carry it out to the dead pile even though it is alive — **← Mova's choice** · **✓ the right answer** · score 10
- **3.** The queen eats it — no support
- **4.** The ant dies at once — score 0

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**Why:** It took the question to ask what happens next. It chose option 2 with score 10, against 5 for the next best. Its support: lesson 330, line 11: «Dead ants give off a smell that tells others to carry them out, which keeps germs away from the nest; scientists dabbed that smell on living ants and their sis…», reached through what followed the sentence the question matched. What matched: the same action «carry out» (+6); the same thing acted on «ants» (+3); the same doer «sisters» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t7/)

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### Test 8 · ★★★ · wrong ✗ {#t8}

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In a hermit crab queue by size, what would happen if the biggest crab did not move into the new shell?

- **1.** Nobody else could move up, and the whole chain would stop — **✓ the right answer** · no support
- **2.** All the crabs would get new shells anyway — score 5
- **3.** The smallest crab would take the big shell — score 4
- **4.** The shell would grow to fit the next crab — **← Mova's choice** · score 6

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**Why:** It took the question to ask what happens next. It chose option 4 with score 6, against 5 for the next best. Its support: lesson 1, line 9: «A hermit crab protects its soft, curled body inside an empty sea snail shell and moves into a bigger shell as it grows; crabs sometimes line up by size and swa…», reached through what followed the sentence the question matched. What matched: the same action «grow» (+6). The right option, 1, 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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t8/)

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### Test 9 · ★★★ · right ✓ {#t9}

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«grown-up stick insect lost a leg, it'll grow back next time it sheds» What is wrong?

- **1.** Grown-up stick insects no longer shed, so the leg will not grow back — **← Mova's choice** · **✓ the right answer** · score 6
- **2.** Legs grow back only on the head — score 3
- **3.** Nothing is wrong, every stick insect regrows any lost leg each week of its life — score 2
- **4.** Stick insects never lose legs — score 0

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**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 330, line 6: «A stick insect has six legs, like every insect, and can drop a leg if grabbed; a young one can grow it back, often smaller, when it next sheds its skin, but gr…», reached through the same lesson line as the sentence the question matched. What matched: the same action «shed» (+4); the same property (+1); 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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t9/)

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### Test 10 · ★★★ · wrong ✗ {#t10}

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«shop's got pretty painted shells for my crab, buying 'em» What is the best advice?

- **1.** The paint makes crabs grow faster — score 8
- **2.** Crabs only move into painted shells — **← Mova's choice** · score 13
- **3.** Painted shells keep crabs healthy — score 4
- **4.** Painted shells can harm crabs; offer plain empty shells — **✓ the right answer** · score 12

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**Why:** It took the question to ask what it is done to. It chose option 2 with score 13, against 12 for the next best. Its support: lesson 1, line 9: «A hermit crab protects its soft, curled body inside an empty sea snail shell and moves into a bigger shell as it grows; crabs sometimes line up by size and swa…», reached through the same lesson line as the sentence the question matched. What matched: the same action «move» (+6); the same place «bigger shell» (+4); the same doer «hermit crab» (+3). The right option, 4, scored 12. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t10/)

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### Test 11 · ★★★ · right ✓ {#t11}

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Why would a snail with only a few big teeth have trouble?

- **1.** Its teeth wear down, so thousands of small ones replaced in rows work better — **← Mova's choice** · **✓ the right answer** · score 5
- **2.** A few big teeth would let it chew through metal and stone, which would hurt it — no support
- **3.** Big teeth would make it too fast — no support
- **4.** Snails do not need to eat at all — score 2

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**Why:** It took the question to ask why something happens (its cause). It chose option 1 with score 5, against 2 for the next best. Its support: lesson 330, line 9: «Snails have a ribbon-shaped tongue covered in thousands of tiny teeth that wear down and are replaced by new rows, and some snails have over 10,000 teeth.», reached through the same lesson line as the sentence the question matched. What matched: the same action «wear down» (+3); the same doer «tiny teeth» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t11/)

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### Test 12 · ★★★ · right ✓ {#t12}

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A stick insect is half a metre long with its legs out. Why might a bird still miss it?

- **1.** It looks and sways like a twig, so the bird ignores it — **← Mova's choice** · **✓ the right answer** · score 5
- **2.** It sings to scare birds — score 4
- **3.** Birds cannot see anything long and thin, only round things — score -1
- **4.** It hides under water — score 0

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**Why:** It took the question to ask why something happens (its cause). It chose option 1 with score 5, against 4 for the next best. Its support: lesson 249, line 13: «Stick insects look like twigs and sway like them in the wind, so birds hunting by sight miss them; the longest insect known is a stick insect from China, over…», reached through the cause of the sentence the question matched. What matched: the same action «look» (+6). 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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/t12/)

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### Exam question 1 · formal language · right ✓ {#e1}

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Identify the reason for which a stick insect falls and remains motionless when disturbed.

- **1.** The insect is commencing hibernation — no support
- **2.** The insect has suffered a permanent injury — no support
- **3.** The insect is seeking food upon the ground — score -2
- **4.** Feigning death causes a predator to lose interest — **← Mova's choice** · **✓ the right answer** · score 6

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**Why:** It took the question to ask which statement is true. It chose option 4 with score 6, against -2 for the next best. Its support: lesson 330, line 7: «A stick insect that falls and lies stiff is playing dead so a hunter loses interest, and some stick insects are among the longest insects in the world, over ha…», reached through the same lesson line as the sentence the question matched. What matched: the same action «lose» (+4); the same thing acted on «interest» (+1); 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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/e1/)

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### Exam question 2 · formal language · wrong ✗ {#e2}

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Select the response consistent with the established facts concerning the removal of dead members from an ant colony.

- **1.** Ants make no provision for their dead — **← Mova's choice** · no support
- **2.** Dead ants emit a chemical signal that prompts others to remove them, thereby protecting the nest from disease — **✓ the right answer** · no support
- **3.** The dead are removed solely because they are visibly motionless, ants recognising death by sight alone — no support
- **4.** The dead are removed solely to provide food for the queen — no support

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**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/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/e2/)

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### Exam question 3 · formal language · right ✓ {#e3}

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Which of the following statements most accurately characterises the vacancy chain observed among hermit crabs?

- **1.** Crabs engage in combat until a single individual remains — score 1
- **2.** Crabs exchange shells at random without regard to size — score 7
- **3.** Crabs construct new shells from sand — score 7
- **4.** Crabs assemble by size and each occupies the shell vacated by the next larger crab — **← Mova's choice** · **✓ the right answer** · score 9

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**Why:** It took the question to ask who or what does it. It chose option 4 with score 9, against 7 for the next best. Its support: lesson 330, line 13: «Wild hermit crabs sometimes queue by size and swap shells one after another, each moving into the shell left by the next biggest; scientists call this a vacanc…», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «shells» (+4); it fills the role the question asks for (+3); the same doer «wild hermit crabs» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/e3/)

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### Exam question 4 · formal language · right ✓ {#e4}

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Ascertain the appropriate course of action in respect of a pet which can no longer be kept.

- **1.** It is to be released into a public park — no support
- **2.** It is to be abandoned at a public place — no support
- **3.** It is to be surrendered to a rescue centre or pet shop which accepts such animals — **← Mova's choice** · **✓ the right answer** · score -2
- **4.** It is to be returned to the wild in the region from which its species originally came — no support

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**Why:** It took the question to ask which statement is true. It chose option 3 with score -2, the only option with support. Its support: lesson 330, line 16: «Pets let go can die or become pests that harm wild animals, and rescue centres and pet shops can take unwanted pets back.», reached through the option's own match among the sentences about the question's things. Against it: a different action (counts against) (-2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/e4/)

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- ← previous: [329. Tortoises, lizards and geckos as pets: heat, lig…](https://md.mova.elamur.ai/free/en/school-run/biology/329-tortoises-lizards-and-geckos-as-pets-heat-light-and-washing-hands/)
- next →: [331. Foods that are dangerous for pets: chocolate, gr…](https://md.mova.elamur.ai/free/en/school-run/biology/331-foods-that-are-dangerous-for-pets-chocolate-grapes-onions-and-lilies/)
- ↑ back to [Biology](https://md.mova.elamur.ai/free/en/school-run/biology/)