---
title: Identify the principal function of the tapetum lucidum in the feline… — How real cats hunt: stalking, waiting… · tree and pragmatics
description: Identify the principal function of the tapetum lucidum in the feline eye. Exam question 1 of lesson 119 «How real cats hunt: stalking, waiting and pouncing» 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 r
---

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# Exam question 1 · How real cats hunt: stalking, waiting and pouncing

<!-- .ven lang=en -->
Identify the principal function of the tapetum lucidum in the feline eye.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 1 · right ✓ · **Who acts:** you · **What happens:** identify · **To what, where:** principal function

<!-- .vabout -->
This is exam question 1 of lesson 119 «How real cats hunt: stalking, waiting and pouncing» 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/119-how-real-cats-hunt/#e1).

## The question {#question}

```conllu
# sent_id = question:biology:119-how-real-cats-hunt:e1:1
# text = Identify the principal function of the tapetum lucidum in the feline eye.
1	Identify	identify	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	function	function	NOUN	NN	Number=Sing	1	obj	_	_
5	of	of	ADP	IN	_	8	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
7	tapetum	tapetum	NOUN	NN	Number=Sing	8	compound	_	_
8	lucidum	lucidum	NOUN	NN	Number=Sing	4	nmod	_	_
9	in	in	ADP	IN	_	12	case	_	_
10	the	the	DET	DT	Definite=Def|PronType=Art	12	det	_	_
11	feline	feline	NOUN	NN	Number=Sing	12	compound	_	_
12	eye	eye	NOUN	NN	Number=Sing	8	nmod	_	SpaceAfter=No
13	.	.	PUNCT	.	_	1	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **identify** | imperative | you *not said here* | the principal function of the tapetum lucidum in the feline eye |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent function=Theme |

<!-- .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 · ✓ the right answer {#o1}

<!-- .ven lang=en -->
It reflects light back through the retina, improving vision in dim light

```conllu
# sent_id = question:biology:119-how-real-cats-hunt:e1:o1:1
# text = It reflects light back through the retina, improving vision in dim light
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	reflects	reflect	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	light	light	NOUN	NN	Number=Sing	2	obj	_	_
4	back	back	ADV	RB	_	2	advmod	_	_
5	through	through	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	retina	retina	NOUN	NN	Number=Sing	2	obl	_	SpaceAfter=No
8	,	,	PUNCT	,	_	9	punct	_	_
9	improving	improve	VERB	VBG	Tense=Pres|VerbForm=Part	2	conj	_	_
10	vision	vision	NOUN	NN	Number=Sing	9	obj	_	_
11	in	in	ADP	IN	_	13	case	_	_
12	dim	dim	ADJ	JJ	Degree=Pos	13	amod	_	_
13	light	light	NOUN	NN	Number=Sing	9	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **reflect back** | present | It | light |  | the retina |  |  | tree rules |
| 2 | **improve** | gerund |  | vision |  | dim light |  |  | vn other\_cos-45.4 «NP V NP.patient»: agent=Agent vision=Patient |

### Option 2 {#o2}

<!-- .ven lang=en -->
It determines the colour of the iris

```conllu
# sent_id = question:biology:119-how-real-cats-hunt:e1:o2:1
# text = It determines the colour of the iris
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	determines	determine	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	colour	colour	NOUN	NN	Number=Sing	2	obj	_	_
5	of	of	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	iris	iris	NOUN	NN	Number=Sing	4	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **determine** | present | It | the colour of the iris |  |  |  |  | vn discover-84 «NP V NP»: agent=Agent colour=Topic |

### Option 3 {#o3}

<!-- .ven lang=en -->
It produces light of its own in conditions of total darkness

```conllu
# sent_id = question:biology:119-how-real-cats-hunt:e1:o3:1
# text = It produces light of its own in conditions of total darkness
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	produces	produce	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	light	light	NOUN	NN	Number=Sing	2	obj	_	_
4	of	of	ADP	IN	_	6	case	_	_
5	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	6	nmod:poss	_	_
6	own	own	ADJ	JJ	Degree=Pos	3	nmod	_	_
7	in	in	ADP	IN	_	8	case	_	_
8	conditions	condition	NOUN	NNS	Number=Plur	2	obl	_	_
9	of	of	ADP	IN	_	11	case	_	_
10	total	total	ADJ	JJ	Degree=Pos	11	amod	_	_
11	darkness	darkness	NOUN	NN	Number=Sing	8	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **produce** | present | It | light of light's own |  | conditions of total darkness |  |  | vn create-26.4 «NP V NP»: agent=Agent light=Result |
| 2 | **condition** |  |  | total darkness |  |  |  |  | nom condition «state transitive»: of=patient |

### Option 4 {#o4}

<!-- .ven lang=en -->
It protects the surface of the eye from dust, grit and other foreign bodies

<!-- fold The tree, 14 words -->
```conllu
# sent_id = question:biology:119-how-real-cats-hunt:e1:o4:1
# text = It protects the surface of the eye from dust, grit and other foreign bodies
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	protects	protect	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	surface	surface	NOUN	NN	Number=Sing	2	obj	_	_
5	of	of	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	eye	eye	NOUN	NN	Number=Sing	4	nmod	_	_
8	from	from	ADP	IN	_	9	case	_	_
9	dust	dust	NOUN	NN	Number=Sing	2	obl	_	SpaceAfter=No
10	,	,	PUNCT	,	_	11	punct	_	_
11	grit	grit	NOUN	NN	Number=Sing	9	conj	_	_
12	and	and	CCONJ	CC	_	15	cc	_	_
13	other	other	ADJ	JJ	Degree=Pos	15	amod	_	_
14	foreign	foreign	ADJ	JJ	Degree=Pos	15	amod	_	_
15	bodies	body	NOUN	NNS	Number=Plur	9	conj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **protect** | present | It | the surface of the eye |  |  |  | from dust and grit and other foreign bodies | vn defend-72.3 «NP V NP PP.theme»: agent=Agent surface=Beneficiary from dust=Theme |

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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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