---
title: Identify the principal means by which the elephantnose fish perceive… — The Congo river: tigerfish, the deepes… · tree and pragmatics
description: Identify the principal means by which the elephantnose fish perceives its surroundings in turbid water. Exam question 2 of lesson 160 «The Congo river: tigerfish, the deepest river, lungfish and hidden birds» of the biology course of Mova's primary school, with the dependency tree and pragmatics of 
---

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# Exam question 2 · The Congo river: tigerfish, the deepest river, lungfish an…

<!-- .ven lang=en -->
Identify the principal means by which the elephantnose fish perceives its surroundings in turbid water.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 4 · wrong ✗ · **Who acts:** you, principal, elephantnose fish · **What happens:** identify, mean, perceive · **To what, where:** surroundings, turbid water

<!-- .vabout -->
This is exam question 2 of lesson 160 «The Congo river: tigerfish, the deepest river, lungfish and hidden birds» 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/160-the-congo-river/#e2).

## The question {#question}

```conllu
# sent_id = question:biology:160-the-congo-river:e2:1
# text = Identify the principal means by which the elephantnose fish perceives its surroundings in turbid water.
1	Identify	identify	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	principal	principal	NOUN	NN	Number=Sing	4	nsubj	_	_
4	means	mean	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	1	ccomp	_	_
5	by	by	ADP	IN	_	6	case	_	_
6	which	which	PRON	WDT	PronType=Rel	10	obl	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
8	elephantnose	elephantnose	NOUN	NN	Number=Sing	9	compound	_	_
9	fish	fish	NOUN	NN	Number=Sing	10	nsubj	_	_
10	perceives	perceive	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	parataxis	_	_
11	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	12	nmod:poss	_	_
12	surroundings	surroundings	NOUN	NNS	Number=Ptan	10	obj	_	_
13	in	in	ADP	IN	_	15	case	_	_
14	turbid	turbid	ADJ	JJ	Degree=Pos	15	amod	_	_
15	water	water	NOUN	NN	Number=Sing	10	obl	_	SpaceAfter=No
16	.	.	PUNCT	.	_	1	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **identify** | imperative | you *not said here* |  |  |  |  |  | vn characterize-29.2-1-1 «NP V S\_ING»: agent=Agent clause=Theme |
| 2 | **mean** | present | the principal |  |  |  |  |  | vn intend-61.2-1 «NP V S»: agent=Agent |
| 3 | **perceive** | present | the elephantnose fish | fish's surroundings |  | turbid water |  |  | vn see-30.1-1 «NP V S»: agent=Experiencer surroundings=Stimulus |

<!-- .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 -->
Vision of exceptional acuity in darkness

```conllu
# sent_id = question:biology:160-the-congo-river:e2:o1:1
# text = Vision of exceptional acuity in darkness
1	Vision	vision	NOUN	NN	Number=Sing	0	root	_	_
2	of	of	ADP	IN	_	4	case	_	_
3	exceptional	exceptional	ADJ	JJ	Degree=Pos	4	amod	_	_
4	acuity	acuity	NOUN	NN	Number=Sing	1	nmod	_	_
5	in	in	ADP	IN	_	6	case	_	_
6	darkness	darkness	NOUN	NN	Number=Sing	4	nmod	_	_
```

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

### Option 2 {#o2}

<!-- .ven lang=en -->
The emission of high-pitched calls and the detection of their echoes from the riverbed

<!-- fold The tree, 15 words -->
```conllu
# sent_id = question:biology:160-the-congo-river:e2:o2:1
# text = The emission of high-pitched calls and the detection of their echoes from the riverbed
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	emission	emission	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	7	case	_	_
4	high	high	ADJ	JJ	Degree=Pos	6	compound	_	SpaceAfter=No
5	-	-	PUNCT	HYPH	_	4	punct	_	SpaceAfter=No
6	pitched	pitch	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	7	amod	_	_
7	calls	call	NOUN	NNS	Number=Plur	2	nmod	_	_
8	and	and	CCONJ	CC	_	10	cc	_	_
9	the	the	DET	DT	Definite=Def|PronType=Art	10	det	_	_
10	detection	detection	NOUN	NN	Number=Sing	7	conj	_	_
11	of	of	ADP	IN	_	13	case	_	_
12	their	their	PRON	PRP$	Case=Gen|Number=Plur|Person=3|Poss=Yes|PronType=Prs	13	nmod:poss	_	_
13	echoes	echo	NOUN	NNS	Number=Plur	10	nmod	_	_
14	from	from	ADP	IN	_	16	case	_	_
15	the	the	DET	DT	Definite=Def|PronType=Art	16	det	_	_
16	riverbed	riverbed	NOUN	NN	Number=Sing	13	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **pitch** | participle |  |  |  |  |  |  | vn throw-17.1-1 «NP V NP»: agent=Agent |
| 2 | **emit** |  |  | pitched calls and the detection of calls's echoes from the riverbed |  |  |  |  | nom emission «act transitive»: of=patient |
| 3 | **detect** |  |  | calls's echoes from the riverbed |  |  |  |  | nom detection «cognition transitive»: of=patient |

### Option 3 {#o3}

<!-- .ven lang=en -->
Contact with the riverbed by means of its fins

```conllu
# sent_id = question:biology:160-the-congo-river:e2:o3:1
# text = Contact with the riverbed by means of its fins
1	Contact	contact	NOUN	NN	Number=Sing	6	nsubj	_	_
2	with	with	ADP	IN	_	4	case	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	riverbed	riverbed	NOUN	NN	Number=Sing	1	nmod	_	_
5	by	by	ADP	IN	_	6	case	_	_
6	means	mean	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
7	of	of	ADP	IN	_	9	case	_	_
8	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	9	nmod:poss	_	_
9	fins	fin	NOUN	NNS	Number=Plur	6	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **mean** | present | Contact with the riverbed |  |  |  |  | of Contact's fins | vn intend-61.2-1 «NP V S»: agent=Agent |

### Option 4 · ✓ the right answer {#o4}

<!-- .ven lang=en -->
The generation of weak electric fields and the detection of their alteration

```conllu
# sent_id = question:biology:160-the-congo-river:e2:o4:1
# text = The generation of weak electric fields and the detection of their alteration
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	generation	generation	NOUN	NN	Number=Sing	0	root	_	_
3	of	of	ADP	IN	_	6	case	_	_
4	weak	weak	ADJ	JJ	Degree=Pos	6	amod	_	_
5	electric	electric	ADJ	JJ	Degree=Pos	6	amod	_	_
6	fields	field	NOUN	NNS	Number=Plur	2	nmod	_	_
7	and	and	CCONJ	CC	_	9	cc	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	detection	detection	NOUN	NN	Number=Sing	6	conj	_	_
10	of	of	ADP	IN	_	12	case	_	_
11	their	their	PRON	PRP$	Case=Gen|Number=Plur|Person=3|Poss=Yes|PronType=Prs	12	nmod:poss	_	_
12	alteration	alteration	NOUN	NN	Number=Sing	9	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **detect** |  |  | fields's alteration |  |  |  |  | nom detection «cognition transitive»: of=patient |
| 2 | **alter** |  | fields *= field* |  |  |  |  |  | nom alteration «event transitive»: poss=agent |

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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.

<!-- /div -->

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