---
title: Ascertain the principal purpose for which the chameleon alters its c… — Snakes and lizards · tree and pragmatics
description: Ascertain the principal purpose for which the chameleon alters its colouration. Exam question 3 of lesson 30 «Snakes and lizards» of the biology course of Mova's primary school, with the dependency tree and pragmatics of the question and of each option; Mova's choice was wrong.
---

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# Exam question 3 · Snakes and lizards

<!-- .ven lang=en -->
Ascertain the principal purpose for which the chameleon alters its colouration.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 2 · wrong ✗ · **Who acts:** you, chameleon · **What happens:** ascertain, alter · **To what, where:** principal purpose, colouration

<!-- .vabout -->
This is exam question 3 of lesson 30 «Snakes and lizards» 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/30-snakes-and-lizards/#e3).

## The question {#question}

```conllu
# sent_id = question:biology:30-snakes-and-lizards:e3:1
# text = Ascertain the principal purpose for which the chameleon alters its colouration.
1	Ascertain	ascertain	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
3	principal	principal	ADJ	JJ	Degree=Pos	4	amod	_	_
4	purpose	purpose	NOUN	NN	Number=Sing	1	obj	_	_
5	for	for	ADP	IN	_	6	case	_	_
6	which	which	PRON	WDT	PronType=Rel	9	obl	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
8	chameleon	chameleon	NOUN	NN	Number=Sing	9	nsubj	_	_
9	alters	alter	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	acl:relcl	_	_
10	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	11	nmod:poss	_	_
11	colouration	colouration	NOUN	NN	Number=Sing	9	obj	_	SpaceAfter=No
12	.	.	PUNCT	.	_	1	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **ascertain** | imperative | you *not said here* | the principal purpose |  |  |  |  | vn discover-84 «NP V NP»: agent=Agent purpose=Topic |
| 2 | **alter** | present | the chameleon | chameleon's colouration |  |  |  | for the principal purpose | vn other\_cos-45.4 «NP V NP.patient»: agent=Agent colouration=Patient |

<!-- .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 · ← Mova's choice {#o1}

<!-- .ven lang=en -->
Concealment against every possible background in which it finds itself

```conllu
# sent_id = question:biology:30-snakes-and-lizards:e3:o1:1
# text = Concealment against every possible background in which it finds itself
1	Concealment	concealment	NOUN	NN	Number=Sing	0	root	_	_
2	against	against	ADP	IN	_	5	case	_	_
3	every	every	DET	DT	PronType=Tot	5	det	_	_
4	possible	possible	ADJ	JJ	Degree=Pos	5	amod	_	_
5	background	background	NOUN	NN	Number=Sing	1	nmod	_	_
6	in	in	ADP	IN	_	7	case	_	_
7	which	which	PRON	WDT	PronType=Rel	9	obl	_	_
8	it	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	9	nsubj	_	_
9	finds	find	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	5	acl:relcl	_	_
10	itself	itself	PRON	PRP	Case=Acc|Gender=Neut|Number=Sing|Person=3|PronType=Prs|Reflex=Yes	9	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **find** | present | background | background |  | every possible background |  |  | vn discover-84 «NP V NP»: agent=Agent itself=Topic |

### Option 2 · ✓ the right answer {#o2}

<!-- .ven lang=en -->
The signalling of mood and the regulation of temperature

```conllu
# sent_id = question:biology:30-snakes-and-lizards:e3:o2:1
# text = The signalling of mood and the regulation of temperature
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	signalling	signalling	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	4	case	_	_
4	mood	mood	NOUN	NN	Number=Sing	2	nmod	_	_
5	and	and	CCONJ	CC	_	7	cc	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	regulation	regulation	NOUN	NN	Number=Sing	2	conj	_	_
8	of	of	ADP	IN	_	9	case	_	_
9	temperature	temperature	NOUN	NN	Number=Sing	7	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **regulate** |  |  | temperature |  |  |  |  | nom regulation «communication transitive»: of=patient |

### Option 3 {#o3}

<!-- .ven lang=en -->
The attraction of rainfall

```conllu
# sent_id = question:biology:30-snakes-and-lizards:e3:o3:1
# text = The attraction of rainfall
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	attraction	attraction	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	4	case	_	_
4	rainfall	rainfall	NOUN	NN	Number=Sing	2	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **attract** |  |  | rainfall |  |  |  |  | nom attraction «phenomenon transitive»: of=patient |

### Option 4 {#o4}

<!-- .ven lang=en -->
The deterrence of the Sun

```conllu
# sent_id = question:biology:30-snakes-and-lizards:e3:o4:1
# text = The deterrence of the Sun
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	deterrence	deterrence	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	5	case	_	_
4	the	the	DET	DT	Definite=Def|PronType=Art	5	det	_	_
5	Sun	Sun	PROPN	NNP	Number=Sing	2	nmod	_	_
```

<!-- .note -->
The frames reader finds no event or fact in this sentence.

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**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.

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