---
title: If a predator disappears, its prey usually increases in number. — Balance in a food web · tree and pragmatics
description: If a predator disappears, its prey usually increases in number. Who acts: predator, prey. A sentence of the lesson «Balance in a food web» of the world course of Mova's primary school with its dependency tree and the pragmatics of every clause.
---

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# Balance in a food web, sentence 9

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If a predator disappears, its prey usually increases in number.

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**Who acts:** predator, prey · **What happens:** disappear, increase · **To what, where:** number

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This is a sentence of the lesson «Balance in a food web» of the world 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 (predator, prey), what happens, when and where, as Mova's frames read it from the tree.

## The tree {#tree}

```conllu
# sent_id = school:world:030-balance-in-food-webs.lesson:9
# text = If a predator disappears, its prey usually increases in number.
# source = school lesson (ours)
# course = world
# lesson = 030-balance-in-food-webs.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): no change
1	If	if	SCONJ	IN	_	4	mark	_	_
2	a	a	DET	DT	Definite=Ind|PronType=Art	3	det	_	_
3	predator	predator	NOUN	NN	Number=Sing	4	nsubj	_	_
4	disappears	disappear	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	9	advcl	_	_
5	,	,	PUNCT	,	_	4	punct	_	_
6	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	7	nmod:poss	_	_
7	prey	prey	NOUN	NN	Number=Sing	9	nsubj	_	_
8	usually	usually	ADV	RB	_	9	advmod	_	_
9	increases	increase	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
10	in	in	ADP	IN	_	11	case	_	_
11	number	number	NOUN	NN	Number=Sing	9	obl	_	_
12	.	.	PUNCT	.	_	9	punct	_	_
```

## Pragmatics {#pragmatics}

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- form: statement
- act: narrate
- voice: narrator
- polarity: none
- teacher: kept the draft

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| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **disappear** *a condition, not said to happen* | present | a predator |  |  |  |  |  | vn disappearance-48.2-1 «NP V»: agent=Theme |
| 2 | **increase** | present | energy's prey |  |  | number |  | usually *property* | vn caused\_calibratable\_cos-45.6.2-1 «NP V ADV-Middle»: agent=Patient |

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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:world:030-balance-in-food-webs.lesson:9`.

**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): no change. **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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