---
title: Ascertain the reason for which the beaver is designated an ecosystem… — Animal builders: beavers, dams and lod… · tree and pragmatics
description: Ascertain the reason for which the beaver is designated an ecosystem engineer. Exam question 4 of lesson 242 «Animal builders: beavers, dams and lodges» 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 right
---

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# Exam question 4 · Animal builders: beavers, dams and lodges

<!-- .ven lang=en -->
Ascertain the reason for which the beaver is designated an ecosystem engineer.

<!-- .vintro -->
**Mova's choice:** option 3 · **The right answer:** option 3 · right ✓ · **Who acts:** you · **What happens:** ascertain, designate · **To what, where:** reason, beaver

<!-- .vabout -->
This is exam question 4 of lesson 242 «Animal builders: beavers, dams and lodges» 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/242-animal-builders-beavers-dams-and-lodges/#e4).

## The question {#question}

```conllu
# sent_id = question:biology:242-animal-builders-beavers-dams-and-lodges:e4:1
# text = Ascertain the reason for which the beaver is designated an ecosystem engineer.
1	Ascertain	ascertain	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	reason	reason	NOUN	NN	Number=Sing	1	obj	_	_
4	for	for	ADP	IN	_	5	case	_	_
5	which	which	PRON	WDT	PronType=Rel	9	obl	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	beaver	beaver	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	designated	designate	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	3	acl:relcl	_	_
10	an	a	DET	DT	Definite=Ind|PronType=Art	12	det	_	_
11	ecosystem	ecosystem	NOUN	NN	Number=Sing	12	compound	_	_
12	engineer	engineer	NOUN	NN	Number=Sing	9	obj	_	SpaceAfter=No
13	.	.	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 reason |  |  |  |  | vn discover-84 «NP V NP»: agent=Agent reason=Topic |
| 2 | **designate** | present · passive |  | the beaver |  |  |  | for the reason | vn appoint-29.1 «NP V NP NP»: subject=Theme engineer=Attribute |

<!-- .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 -->
It confines its activity exclusively to its own lodge

```conllu
# sent_id = question:biology:242-animal-builders-beavers-dams-and-lodges:e4:o1:1
# text = It confines its activity exclusively to its own lodge
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	confines	confine	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	4	nmod:poss	_	_
4	activity	activity	NOUN	NN	Number=Sing	2	obj	_	_
5	exclusively	exclusively	ADV	RB	_	2	advmod	_	_
6	to	to	ADP	IN	_	9	case	_	_
7	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	9	nmod:poss	_	_
8	own	own	ADJ	JJ	Degree=Pos	9	amod	_	_
9	lodge	lodge	NOUN	NN	Number=Sing	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **confine** | present | It | its activity |  | activity's own lodge |  | exclusively *property* | vn confine-92-1 «NP V NP PP.destination»: agent=Agent activity=Theme to lodge=Destination |

### Option 2 {#o2}

<!-- .ven lang=en -->
It is employed by engineers in the construction of bridges across wide rivers

```conllu
# sent_id = question:biology:242-animal-builders-beavers-dams-and-lodges:e4:o2:1
# text = It is employed by engineers in the construction of bridges across wide rivers
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	3	nsubj:pass	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	aux:pass	_	_
3	employed	employ	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	_	_
4	by	by	ADP	IN	_	5	case	_	_
5	engineers	engineer	NOUN	NNS	Number=Plur	3	obl	_	_
6	in	in	ADP	IN	_	8	case	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
8	construction	construction	NOUN	NN	Number=Sing	3	obl	_	_
9	of	of	ADP	IN	_	10	case	_	_
10	bridges	bridge	NOUN	NNS	Number=Plur	8	nmod	_	_
11	across	across	ADP	IN	_	13	case	_	_
12	wide	wide	ADJ	JJ	Degree=Pos	13	amod	_	_
13	rivers	river	NOUN	NNS	Number=Plur	3	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **employ** | present · passive | engineers | It |  | the construction of bridges |  | across wide rivers | vn hire-13.5.3 «NP V NP»: agent=Agent subject=Theme |
| 2 | **construct** |  |  | bridges |  |  |  |  | nom construction «act transitive»: of=patient |

### Option 3 · ← Mova's choice · ✓ the right answer {#o3}

<!-- .ven lang=en -->
Its works alter the landscape and furnish habitats for numerous other species

```conllu
# sent_id = question:biology:242-animal-builders-beavers-dams-and-lodges:e4:o3:1
# text = Its works alter the landscape and furnish habitats for numerous other species
1	Its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	2	nmod:poss	_	_
2	works	work	NOUN	NNS	Number=Plur	3	nsubj	_	_
3	alter	alter	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
4	the	the	DET	DT	Definite=Def|PronType=Art	5	det	_	_
5	landscape	landscape	NOUN	NN	Number=Sing	3	obj	_	_
6	and	and	CCONJ	CC	_	7	cc	_	_
7	furnish	furnish	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	3	conj	_	_
8	habitats	habitat	NOUN	NNS	Number=Plur	7	obj	_	_
9	for	for	ADP	IN	_	12	case	_	_
10	numerous	numerous	ADJ	JJ	Degree=Pos	12	amod	_	_
11	other	other	ADJ	JJ	Degree=Pos	12	amod	_	_
12	species	species	NOUN	NNS	Number=Plur	7	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **alter** | present | Its works | the landscape |  |  |  |  | vn other\_cos-45.4 «NP V NP.patient»: agent=Agent landscape=Patient |
| 2 | **furnish** | present | Its works *not said here* | habitats |  |  |  | for numerous other species | vn fulfilling-13.4.1-1 «NP V NP PP.recipient»: agent=Agent habitat=Theme for species=Recipient |
| 3 | **work** |  | Its *= it* |  |  |  |  |  | nom work «act intransitive»: poss=agent |

### Option 4 {#o4}

<!-- .ven lang=en -->
It removes all vegetation from the banks of rivers

```conllu
# sent_id = question:biology:242-animal-builders-beavers-dams-and-lodges:e4:o4:1
# text = It removes all vegetation from the banks of rivers
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	removes	remove	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	all	all	DET	DT	PronType=Tot	4	det	_	_
4	vegetation	vegetation	NOUN	NN	Number=Sing	2	obj	_	_
5	from	from	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	banks	bank	NOUN	NNS	Number=Plur	2	obl	_	_
8	of	of	ADP	IN	_	9	case	_	_
9	rivers	river	NOUN	NNS	Number=Plur	7	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **remove** | present | It | all vegetation |  | the banks of rivers |  |  | vn fire-10.10 «NP V NP PP.source»: agent=Agent vegetation=Theme from bank=Source |

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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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