---
title: A sea otter floats on its back cracking a sea urchin. Why is that go… — Food chains: sun, plants, plant-eaters… · tree and pragmatics
description: A sea otter floats on its back cracking a sea urchin. Why is that good for the kelp forest? Test 9 · ★ of lesson 46 «Food chains: sun, plants, plant-eaters, meat-eaters» of the biology course of Mova's primary school, with the dependency tree and pragmatics of the question and of each option; Mova's
---

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# Test 9 · ★ · Food chains: sun, plants, plant-eaters, meat-eaters

<!-- .ven lang=en -->
A sea otter floats on its back cracking a sea urchin. Why is that good for the kelp forest?

<!-- .vintro -->
**Mova's choice:** option 4 · **The right answer:** option 4 · right ✓ · **Who acts:** sea otter · **What happens:** float, crack, be · **To what, where:** back, sea urchin

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This is test 9 · ★ of lesson 46 «Food chains: sun, plants, plant-eaters, meat-eaters» of the biology course of Mova's primary school. 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/46-food-chains/#t9).

## The question {#question}

<!-- .note -->
*Sentence 1:* A sea otter floats on its back cracking a sea urchin.

```conllu
# sent_id = question:biology:46-food-chains:t9:1
# text = A sea otter floats on its back cracking a sea urchin.
1	A	a	DET	DT	Definite=Ind|PronType=Art	3	det	_	_
2	sea	sea	NOUN	NN	Number=Sing	3	compound	_	_
3	otter	otter	NOUN	NN	Number=Sing	4	nsubj	_	_
4	floats	float	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
5	on	on	ADP	IN	_	7	case	_	_
6	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	7	nmod:poss	_	_
7	back	back	NOUN	NN	Number=Sing	4	obl	_	_
8	cracking	crack	VERB	VBG	VerbForm=Ger	4	advcl	_	_
9	a	a	DET	DT	Definite=Ind|PronType=Art	11	det	_	_
10	sea	sea	NOUN	NN	Number=Sing	11	compound	_	_
11	urchin	urchin	NOUN	NN	Number=Sing	8	obj	_	SpaceAfter=No
12	.	.	PUNCT	.	_	4	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **float** | present | a sea otter |  |  | otter's back |  |  | vn run-51.3.2-2 «NP V PP.location»: agent=Theme on back=Trajectory |
| 2 | **crack** | gerund | a sea otter *not said here* | a sea urchin |  |  |  |  | vn sound\_emission-43.2 «PP.location V NP»: agent=Location urchin=Theme |

<!-- .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.

<!-- .note -->
*Sentence 2:* Why is that good for the kelp forest?

```conllu
# sent_id = question:biology:46-food-chains:t9:2
# text = Why is that good for the kelp forest?
1	Why	why	ADV	WRB	PronType=Int	4	advmod	_	_
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	cop	_	_
3	that	that	SCONJ	IN	_	4	mark	_	_
4	good	good	ADJ	JJ	Degree=Pos	0	root	_	_
5	for	for	ADP	IN	_	8	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
7	kelp	kelp	NOUN	NN	Number=Sing	8	compound	_	_
8	forest	forest	NOUN	NN	Number=Sing	4	obl	_	SpaceAfter=No
9	?	?	PUNCT	.	_	4	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is** | present |  |  |  |  |  | for the kelp forest; good *property* | tree rules |

## The options {#options}

### Option 1 {#o1}

<!-- .ven lang=en -->
The broken urchin shells sink and feed the kelp

```conllu
# sent_id = question:biology:46-food-chains:t9:o1:1
# text = The broken urchin shells sink and feed the kelp
1	The	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
2	broken	break	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	3	amod	_	_
3	urchin	urchin	NOUN	NN	Number=Sing	4	compound	_	_
4	shells	shell	NOUN	NNS	Number=Plur	5	nsubj	_	_
5	sink	sink	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
6	and	and	CCONJ	CC	_	7	cc	_	_
7	feed	feed	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	5	conj	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	kelp	kelp	NOUN	NN	Number=Sing	7	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **break** | participle |  |  |  |  |  |  | vn hurt-40.8.3-1-1 «NP V»: agent=Patient |
| 2 | **sink** | present | the urchin shells |  |  |  |  |  | vn other\_cos-45.4 «NP.patient V»: agent=Patient |
| 3 | **feed** | present | the urchin shells *not said here* | the kelp |  |  |  |  | vn feeding-39.7 «NP V NP»: agent=Agent kelp=Recipient |

### Option 2 {#o2}

<!-- .ven lang=en -->
It is not, because otters eat lots of kelp too

```conllu
# sent_id = question:biology:46-food-chains:t9:o2:1
# text = It is not, because otters eat lots of kelp too
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	is	be	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	not	not	PART	RB	Polarity=Neg	2	advmod	_	SpaceAfter=No
4	,	,	PUNCT	,	_	7	punct	_	_
5	because	because	SCONJ	IN	_	7	mark	_	_
6	otters	otter	NOUN	NNS	Number=Plur	7	nsubj	_	_
7	eat	eat	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	2	parataxis	_	_
8	lots	lot	NOUN	NNS	Number=Plur	7	obj	_	_
9	of	of	ADP	IN	_	10	case	_	_
10	kelp	kelp	NOUN	NN	Number=Sing	8	nmod	_	_
11	too	too	ADV	RB	_	7	advmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **not** **be** | present | It |  |  |  |  |  | vn exist-47.1 «NP V»: agent=Theme |
| 2 | **eat** | present | otters | lots of kelp |  |  |  |  | vn eat-39.1-1 «NP V NP»: agent=Agent lot=Patient |

### Option 3 {#o3}

<!-- .ven lang=en -->
Otters plant new kelp using their little stones

```conllu
# sent_id = question:biology:46-food-chains:t9:o3:1
# text = Otters plant new kelp using their little stones
1	Otters	otter	NOUN	NNS	Number=Plur	2	nsubj	_	_
2	plant	plant	VERB	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	new	new	ADJ	JJ	Degree=Pos	4	amod	_	_
4	kelp	kelp	NOUN	NN	Number=Sing	2	obj	_	_
5	using	use	VERB	VBG	Tense=Pres|VerbForm=Part	2	advcl	_	_
6	their	their	PRON	PRP$	Case=Gen|Number=Plur|Person=3|Poss=Yes|PronType=Prs	8	nmod:poss	_	_
7	little	little	ADJ	JJ	Degree=Pos	8	amod	_	_
8	stones	stone	NOUN	NNS	Number=Plur	5	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **plant** | present | Otters | new kelp |  |  |  |  | vn establish-55.5-1 «NP V NP»: agent=Agent kelp=Patient |
| 2 | **use** | gerund | Otters *not said here* | Otters's little stones |  |  |  |  | vn eat-39.1 «NP V NP»: agent=Agent stone=Patient |

### Option 4 · ← Mova's choice · ✓ the right answer {#o4}

<!-- .ven lang=en -->
Fewer urchins means less kelp gets eaten

```conllu
# sent_id = question:biology:46-food-chains:t9:o4:1
# text = Fewer urchins means less kelp gets eaten
1	Fewer	few	ADJ	JJR	Degree=Cmp	2	amod	_	_
2	urchins	urchin	NOUN	NNS	Number=Plur	3	nsubj	_	_
3	means	mean	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
4	less	less	ADJ	JJR	Degree=Cmp	5	amod	_	_
5	kelp	kelp	NOUN	NN	Number=Sing	7	nsubj:pass	_	_
6	gets	get	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	7	aux:pass	_	_
7	eaten	eat	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	3	ccomp	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **mean** | present | Fewer urchins |  |  |  |  |  | vn intend-61.2-1 «NP V S»: agent=Agent clause=Topic |
| 2 | **eat** | present · passive |  | less kelp |  |  |  |  | vn eat-39.1-1 «NP V NP»: subject=Patient |

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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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