---
title: Which of the following statements most accurately characterises the… — Unusual pets: stick insects, giant sna… · tree and pragmatics
description: Which of the following statements most accurately characterises the vacancy chain observed among hermit crabs? Exam question 3 of lesson 330 «Unusual pets: stick insects, giant snails, ant farms and hermit crabs» of the biology course of Mova's primary school, with the dependency tree and pragmatics
---

<!-- md -->
[Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/e3/)

<!-- crumbs -->
[home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [questions](https://md.mova.elamur.ai/free/en/corpora/questions/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/questions/biology/) / [Unusual pets: stick insects, giant sna…](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/) / e3

# Exam question 3 · Unusual pets: stick insects, giant snails, ant farms and h…

<!-- .ven lang=en -->
Which of the following statements most accurately characterises the vacancy chain observed among hermit crabs?

<!-- .vintro -->
**Mova's choice:** option 4 · **The right answer:** option 4 · right ✓ · **What happens:** follow, characteris, observe · **To what, where:** vacancy chain

<!-- .vabout -->
This is exam question 3 of lesson 330 «Unusual pets: stick insects, giant snails, ant farms and hermit crabs» of the biology course of Mova's primary school, asked in stiff, formal language. The page gives the question's syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause, then the 4 options as the student saw them, each with its tree and pragmatics. Every text is parsed by Mova itself. How the student answered it, with the score of every option and why: [the test at school](https://md.mova.elamur.ai/free/en/school-run/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/#e3).

## The question {#question}

```conllu
# sent_id = question:biology:330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs:e3:1
# text = Which of the following statements most accurately characterises the vacancy chain observed among hermit crabs?
1	Which	which	PRON	WDT	PronType=Rel	8	nsubj	_	_
2	of	of	ADP	IN	_	5	case	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	5	det	_	_
4	following	follow	VERB	VBG	VerbForm=Ger	5	amod	_	_
5	statements	statement	NOUN	NNS	Number=Plur	8	obl	_	_
6	most	most	ADV	RBS	Degree=Sup	7	advmod	_	_
7	accurately	accurately	ADV	RB	_	8	advmod	_	_
8	characterises	characteris	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
9	the	the	DET	DT	Definite=Def|PronType=Art	11	det	_	_
10	vacancy	vacancy	NOUN	NN	Number=Sing	11	compound	_	_
11	chain	chain	NOUN	NN	Number=Sing	8	obj	_	_
12	observed	observe	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	11	acl	_	_
13	among	among	ADP	IN	_	15	case	_	_
14	hermit	hermit	NOUN	NN	Number=Sing	15	compound	_	_
15	crabs	crab	NOUN	NNS	Number=Plur	12	obl	_	SpaceAfter=No
16	?	?	PUNCT	.	_	8	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **follow** | gerund |  |  |  |  |  |  | vn occur-48.3-1 «NP V»: agent=Theme |
| 2 | **characteris** | present |  | the vacancy chain |  |  |  | of the following statements; accurately *property* | tree rules |
| 3 | **observe** | participle |  | the vacancy chain *not said here* |  |  |  | among hermit crabs | vn say-37.7-1-1 «NP V that S»: agent=Agent |

<!-- .note -->
One row per clause the reader finds. «not said here»: a role filled from the clause above. «roles by»: a VerbNet class and frame when one fits the verb, else the reader's rules on the tree.

## The options {#options}

### Option 1 {#o1}

<!-- .ven lang=en -->
Crabs engage in combat until a single individual remains

```conllu
# sent_id = question:biology:330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs:e3:o1:1
# text = Crabs engage in combat until a single individual remains
1	Crabs	crab	NOUN	NNS	Number=Plur	2	nsubj	_	_
2	engage	engage	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	in	in	ADP	IN	_	4	case	_	_
4	combat	combat	NOUN	NN	Number=Sing	2	obl	_	_
5	until	until	ADP	IN	_	9	case	_	_
6	a	a	DET	DT	Definite=Ind|PronType=Art	9	det	_	_
7	single	single	ADJ	JJ	Degree=Pos	9	amod	_	_
8	individual	individual	ADJ	JJ	Degree=Pos	9	amod	_	_
9	remains	remains	NOUN	NNS	Number=Ptan	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **engage** | present | Crabs |  |  |  | until a single individual remains | in combat *goal* | vn involve-107.1 «NP V NP PP.goal»: agent=Agent in combat=Goal |

### Option 2 {#o2}

<!-- .ven lang=en -->
Crabs exchange shells at random without regard to size

```conllu
# sent_id = question:biology:330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs:e3:o2:1
# text = Crabs exchange shells at random without regard to size
1	Crabs	crab	NOUN	NNS	Number=Plur	2	nsubj	_	_
2	exchange	exchange	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	shells	shell	NOUN	NNS	Number=Plur	2	obj	_	_
4	at	at	ADP	IN	_	5	case	_	_
5	random	random	NOUN	NN	Number=Sing	2	obl	_	_
6	without	without	ADP	IN	_	7	case	_	_
7	regard	regard	NOUN	NN	Number=Sing	2	obl	_	_
8	to	to	PART	TO	_	9	mark	_	_
9	size	size	NOUN	NN	Number=Sing	7	acl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **exchange** | present | Crabs | shells |  | random |  | without regard | vn exchange-13.6.1 «NP V NP»: agent=Agent shell=Theme |

### Option 3 {#o3}

<!-- .ven lang=en -->
Crabs construct new shells from sand

```conllu
# sent_id = question:biology:330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs:e3:o3:1
# text = Crabs construct new shells from sand
1	Crabs	crab	NOUN	NNS	Number=Plur	2	nsubj	_	_
2	construct	construct	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	new	new	ADJ	JJ	Degree=Pos	4	amod	_	_
4	shells	shell	NOUN	NNS	Number=Plur	2	obj	_	_
5	from	from	ADP	IN	_	6	case	_	_
6	sand	sand	NOUN	NN	Number=Sing	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **construct** | present | Crabs | new shells |  | sand |  |  | vn create-26.4 «NP V NP PP.material»: agent=Agent shell=Result from sand=Material |

### Option 4 · ← Mova's choice · ✓ the right answer {#o4}

<!-- .ven lang=en -->
Crabs assemble by size and each occupies the shell vacated by the next larger crab

<!-- fold The tree, 15 words -->
```conllu
# sent_id = question:biology:330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs:e3:o4:1
# text = Crabs assemble by size and each occupies the shell vacated by the next larger crab
1	Crabs	crab	NOUN	NNS	Number=Plur	2	nsubj	_	_
2	assemble	assemble	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	by	by	ADP	IN	_	4	case	_	_
4	size	size	NOUN	NN	Number=Sing	2	obl	_	_
5	and	and	CCONJ	CC	_	9	cc	_	_
6	each	each	DET	DT	PronType=Tot	9	det	_	_
7	occupies	occupy	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	9	cop	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	shell	shell	NOUN	NN	Number=Sing	4	conj	_	_
10	vacated	vacate	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	9	acl	_	_
11	by	by	ADP	IN	_	15	case	_	_
12	the	the	DET	DT	Definite=Def|PronType=Art	15	det	_	_
13	next	next	ADJ	JJ	Degree=Pos	15	amod	_	_
14	larger	large	ADJ	JJR	Degree=Cmp	15	amod	_	_
15	crab	crab	NOUN	NN	Number=Sing	10	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **assemble** | present | Crabs |  |  |  |  | by size and each shell | vn herd-47.5.2 «NP V NP.theme»: agent=Agent |
| 2 | **is a** | present | Crabs *not said here* | each shell |  |  |  |  | tree rules |
| 3 | **vacate** | participle |  | each shell *not said here* |  |  |  | by the next larger crab | vn escape-51.1-1-1 «NP V»: agent=Theme |

<!-- div src -->

**Text:** the tests of Mova's primary school, written for Mova (`world/data/school/`), as the course runner gave them to the student. **Trees:** Mova's own parse — the `en` model on the CPU, when the site is built — not checked by a teacher; they may be wrong. **Frames:** Mova's frames reader (`prag`), each text read on its own. Elamur Cosmic License.

<!-- /div -->

<!-- pn -->
- ← previous: [Unusual pets: stick insects, giant sna…, exam 2](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/e2/)
- next →: [Unusual pets: stick insects, giant sna…, exam 4](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/e4/)
- ↑ back to [Unusual pets: stick insects, giant snails, ant farms and hermit crabs](https://md.mova.elamur.ai/free/en/corpora/questions/biology/330-unusual-pets-stick-insects-giant-snails-ant-farms-and-hermit-crabs/)