---
title: An animal that keeps a whole habitat in balance, like the sea otter,… — Sea lions, seals and otters · tree and pragmatics
description: An animal that keeps a whole habitat in balance, like the sea otter, is called a keystone species. Who acts: animal. A sentence of the lesson «Sea lions, seals and otters» of the biology course of Mova's primary school with its dependency tree and the pragmatics of every clause.
---

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# Sea lions, seals and otters, sentence 14

<!-- .ven lang=en -->
An animal that keeps a whole habitat in balance, like the sea otter, is called a keystone species.

<!-- .vintro -->
**Who acts:** animal · **What happens:** keep, call · **To what, where:** whole habitat, balance, animal · **Speech:** someone speaks here

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This is a sentence of the lesson «Sea lions, seals and otters» of the biology course of Mova's primary school. The page gives its syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause: who acts (animal), what happens, when and where, as Mova's frames read it from the tree.

## The tree {#tree}

```conllu
# sent_id = school:biology:100-sea-lions-seals-and-otters.lesson:14
# text = An animal that keeps a whole habitat in balance, like the sea otter, is called a keystone species.
# source = school lesson (ours)
# course = biology
# lesson = 100-sea-lions-seals-and-otters.lesson
# annotation = Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): R7-rel-agree ×1
1	An	a	DET	DT	Definite=Ind|PronType=Art	2	det	_	_
2	animal	animal	NOUN	NN	Number=Sing	17	nsubj:pass	_	_
3	that	that	PRON	WDT	PronType=Rel	4	nsubj	_	_
4	keeps	keep	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	2	acl:relcl	_	_
5	a	a	DET	DT	Definite=Ind|PronType=Art	7	det	_	_
6	whole	whole	ADJ	JJ	Degree=Pos	7	amod	_	_
7	habitat	habitat	NOUN	NN	Number=Sing	4	obj	_	_
8	in	in	ADP	IN	_	9	case	_	_
9	balance	balance	NOUN	NN	Number=Sing	4	obl	_	_
10	,	,	PUNCT	,	_	14	punct	_	_
11	like	like	ADP	IN	_	14	case	_	_
12	the	the	DET	DT	Definite=Def|PronType=Art	14	det	_	_
13	sea	sea	NOUN	NN	Number=Sing	14	compound	_	_
14	otter	otter	NOUN	NN	Number=Sing	9	appos	_	_
15	,	,	PUNCT	,	_	2	punct	_	_
16	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	17	aux:pass	_	_
17	called	call	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	_	_
18	a	a	DET	DT	Definite=Ind|PronType=Art	20	det	_	_
19	keystone	keystone	NOUN	NN	Number=Sing	20	compound	_	_
20	species	species	NOUN	NN	Number=Sing	17	xcomp	_	Agree=R7-rel-agree|Haiku=17:obj
21	.	.	PUNCT	.	_	17	punct	_	_
```

## Pragmatics {#pragmatics}

<!-- .note -->
No stored speech act for this sentence.

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **keep** | present | a animal | a whole habitat |  | balance |  |  | vn keep-15.2 «NP V NP PP.location»: agent=Agent habitat=Theme in balance=Location |
| 2 | **call** | present · passive |  | a animal |  |  |  |  | vn initiate\_communication-37.4.2-1 «NP V NP.recipient»: subject=Recipient |

<!-- .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.

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**Licence: [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)**, as the whole of Mova corpus 0.4, of which this treebank (the agreed school, `mova-school-agreed-en.conllu`) is part. The lessons were written for Mova's primary school. Sentence `school:biology:100-sea-lions-seals-and-otters.lesson:14`.

**The tree:** Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): R7-rel-agree ×1. **The frames** are read from the tree by Mova's frames reader (`prag`) when this page is built, the lesson read in order, so a pronoun may be resolved from an earlier sentence.

See the [release 0.4](https://md.mova.elamur.ai/free/en/releases/0.4/).

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