---
title: Ascertain the principal reason for which sound is preferred to light… — Echolocation in the sea and in people:… · tree and pragmatics
description: Ascertain the principal reason for which sound is preferred to light for the detection of objects in the deep sea. Exam question 4 of lesson 230 «Echolocation in the sea and in people: dolphins, whales, swiftlets and clicking humans» of the biology course of Mova's primary school, with the dependenc
---

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# Exam question 4 · Echolocation in the sea and in people: dolphins, whales, s…

<!-- .ven lang=en -->
Ascertain the principal reason for which sound is preferred to light for the detection of objects in the deep sea.

<!-- .vintro -->
**Mova's choice:** option 2 · **The right answer:** option 1 · wrong ✗ · **Who acts:** you · **What happens:** ascertain, prefer, detect · **To what, where:** principal reason, sound, deep sea, objects

<!-- .vabout -->
This is exam question 4 of lesson 230 «Echolocation in the sea and in people: dolphins, whales, swiftlets and clicking humans» 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/230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans/#e4).

## The question {#question}

```conllu
# sent_id = question:biology:230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans:e4:1
# text = Ascertain the principal reason for which sound is preferred to light for the detection of objects in the deep sea.
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	reason	reason	NOUN	NN	Number=Sing	1	obj	_	_
5	for	for	ADP	IN	_	6	case	_	_
6	which	which	PRON	WDT	PronType=Rel	9	obl	_	_
7	sound	sound	NOUN	NN	Number=Sing	9	nsubj:pass	_	_
8	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	9	aux:pass	_	_
9	preferred	prefer	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	4	acl:relcl	_	_
10	to	to	ADP	IN	_	11	case	_	_
11	light	light	NOUN	NN	Number=Sing	9	obl	_	_
12	for	for	ADP	IN	_	14	case	_	_
13	the	the	DET	DT	Definite=Def|PronType=Art	14	det	_	_
14	detection	detection	NOUN	NN	Number=Sing	9	obl	_	_
15	of	of	ADP	IN	_	16	case	_	_
16	objects	object	NOUN	NNS	Number=Plur	14	nmod	_	_
17	in	in	ADP	IN	_	20	case	_	_
18	the	the	DET	DT	Definite=Def|PronType=Art	20	det	_	_
19	deep	deep	ADJ	JJ	Degree=Pos	20	amod	_	_
20	sea	sea	NOUN	NN	Number=Sing	9	obl	_	SpaceAfter=No
21	.	.	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 reason |  |  |  |  | vn discover-84 «NP V NP»: agent=Agent reason=Topic |
| 2 | **prefer** | present · passive |  | sound |  | the deep sea |  | for the principal reason; to light; for the detection of objects | vn admire-31.2 «NP V NP PP.attribute»: subject=Stimulus for which=Attribute |
| 3 | **detect** |  |  | objects |  |  |  |  | nom detection «cognition transitive»: of=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 · ✓ the right answer {#o1}

<!-- .ven lang=en -->
Light is rapidly extinguished in water, whereas sound is propagated far and swiftly

```conllu
# sent_id = question:biology:230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans:e4:o1:1
# text = Light is rapidly extinguished in water, whereas sound is propagated far and swiftly
1	Light	light	NOUN	NN	Number=Sing	4	nsubj	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	cop	_	_
3	rapidly	rapidly	ADV	RB	_	4	advmod	_	_
4	extinguished	extinguished	ADJ	JJ	Degree=Pos	0	root	_	_
5	in	in	ADP	IN	_	6	case	_	_
6	water	water	NOUN	NN	Number=Sing	4	obl	_	SpaceAfter=No
7	,	,	PUNCT	,	_	11	punct	_	_
8	whereas	whereas	SCONJ	IN	_	11	mark	_	_
9	sound	sound	NOUN	NN	Number=Sing	11	nsubj:pass	_	_
10	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	11	aux:pass	_	_
11	propagated	propagate	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	4	conj	_	_
12	far	far	ADV	RB	Degree=Pos	11	advmod	_	_
13	and	and	CCONJ	CC	_	14	cc	_	_
14	swiftly	swiftly	ADV	RB	_	12	conj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is** | present | Light |  |  | water |  | extinguished, rapidly *property* | tree rules |
| 2 | **propagate** | present · passive |  | sound |  |  |  | far *property* | vn entity\_specific\_modes\_being-47.2 «NP.location V NP»: subject=Theme |

### Option 2 · ← Mova's choice {#o2}

<!-- .ven lang=en -->
Water amplifies light but absorbs sound, thereby rendering sound of little use at great depth

<!-- fold The tree, 15 words -->
```conllu
# sent_id = question:biology:230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans:e4:o2:1
# text = Water amplifies light but absorbs sound, thereby rendering sound of little use at great depth
1	Water	water	NOUN	NN	Number=Sing	2	nsubj	_	_
2	amplifies	amplify	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	light	light	NOUN	NN	Number=Sing	2	obj	_	_
4	but	but	CCONJ	CC	_	5	cc	_	_
5	absorbs	absorb	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	2	conj	_	_
6	sound	sound	NOUN	NN	Number=Sing	5	obj	_	SpaceAfter=No
7	,	,	PUNCT	,	_	10	punct	_	_
8	thereby	thereby	ADV	RB	_	9	advmod	_	_
9	rendering	render	VERB	VBG	VerbForm=Ger	10	amod	_	_
10	sound	sound	NOUN	NN	Number=Sing	13	nsubj	_	_
11	of	of	ADP	IN	_	12	case	_	_
12	little	little	ADJ	JJ	Degree=Pos	10	nmod	_	_
13	use	use	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	5	parataxis	_	_
14	at	at	ADP	IN	_	16	case	_	_
15	great	great	ADJ	JJ	Degree=Pos	16	amod	_	_
16	depth	depth	NOUN	NN	Number=Sing	13	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **amplify** | present | Water | light |  |  |  |  | vn other\_cos-45.4 «NP V NP.patient»: agent=Agent light=Patient |
| 2 | **absorb** | present | Water *not said here* | sound |  |  |  |  | vn absorb-39.8 «NP V NP»: agent=Goal sound=Theme |
| 3 | **render** | gerund |  |  |  |  |  | thereby *property* | vn give-13.1 «NP V PP.recipient»: agent=Agent |
| 4 | **use** | present | rendering sound of little |  |  | great depth |  |  | vn eat-39.1 «NP V»: agent=Agent |

### Option 3 {#o3}

<!-- .ven lang=en -->
Light travels more slowly in water than sound

```conllu
# sent_id = question:biology:230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans:e4:o3:1
# text = Light travels more slowly in water than sound
1	Light	light	NOUN	NN	Number=Sing	2	nsubj	_	_
2	travels	travel	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	more	more	ADV	RBR	Degree=Cmp	4	advmod	_	_
4	slowly	slowly	ADV	RB	_	2	advmod	_	_
5	in	in	ADP	IN	_	6	case	_	_
6	water	water	NOUN	NN	Number=Sing	2	obl	_	_
7	than	than	ADP	IN	_	8	case	_	_
8	sound	sound	NOUN	NN	Number=Sing	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **travel** | present | Light |  |  | water |  | than sound; slowly *property* | vn run-51.3.2-1 «NP V PP.location»: agent=Theme in water=Trajectory |

### Option 4 {#o4}

<!-- .ven lang=en -->
Sound is visible to marine animals

```conllu
# sent_id = question:biology:230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans:e4:o4:1
# text = Sound is visible to marine animals
1	Sound	sound	NOUN	NN	Number=Sing	3	nsubj	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	cop	_	_
3	visible	visible	ADJ	JJ	Degree=Pos	0	root	_	_
4	to	to	ADP	IN	_	6	case	_	_
5	marine	marine	ADJ	JJ	Degree=Pos	6	amod	_	_
6	animals	animal	NOUN	NNS	Number=Plur	3	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is** | present | Sound |  |  |  |  | to marine animals; visible *property* | tree rules |

<!-- 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 -->

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- ← previous: [Echolocation in the sea and in people:…, exam 3](https://md.mova.elamur.ai/free/en/corpora/questions/biology/230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans/e3/)
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- ↑ back to [Echolocation in the sea and in people: dolphins, whales, swiftlets and clicking humans](https://md.mova.elamur.ai/free/en/corpora/questions/biology/230-echolocation-in-the-sea-and-in-people-dolphins-whales-swiftlets-and-clicking-humans/)