---
title: Ascertain the origin of a considerable proportion of the white sand… — Coral reef builders: polyps, bleaching… · tree and pragmatics
description: Ascertain the origin of a considerable proportion of the white sand upon certain tropical beaches. Exam question 4 of lesson 172 «Coral reef builders: polyps, bleaching, sand from parrotfish and giant clams» of the biology course of Mova's primary school, with the dependency tree and pragmatics of t
---

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# Exam question 4 · Coral reef builders: polyps, bleaching, sand from parrotfi…

<!-- .ven lang=en -->
Ascertain the origin of a considerable proportion of the white sand upon certain tropical beaches.

<!-- .vintro -->
**Mova's choice:** option 1 · **The right answer:** option 1 · right ✓ · **Who acts:** you · **What happens:** ascertain · **To what, where:** origin

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This is exam question 4 of lesson 172 «Coral reef builders: polyps, bleaching, sand from parrotfish and giant clams» 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/172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams/#e4).

## The question {#question}

```conllu
# sent_id = question:biology:172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams:e4:1
# text = Ascertain the origin of a considerable proportion of the white sand upon certain tropical beaches.
1	Ascertain	ascertain	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	origin	origin	NOUN	NN	Number=Sing	1	obj	_	_
4	of	of	ADP	IN	_	7	case	_	_
5	a	a	DET	DT	Definite=Ind|PronType=Art	7	det	_	_
6	considerable	considerable	ADJ	JJ	Degree=Pos	7	amod	_	_
7	proportion	proportion	NOUN	NN	Number=Sing	3	nmod	_	_
8	of	of	ADP	IN	_	11	case	_	_
9	the	the	DET	DT	Definite=Def|PronType=Art	11	det	_	_
10	white	white	ADJ	JJ	Degree=Pos	11	amod	_	_
11	sand	sand	NOUN	NN	Number=Sing	7	nmod	_	_
12	upon	upon	ADP	IN	_	15	case	_	_
13	certain	certain	ADJ	JJ	Degree=Pos	15	amod	_	_
14	tropical	tropical	ADJ	JJ	Degree=Pos	15	amod	_	_
15	beaches	beach	NOUN	NNS	Number=Plur	11	nmod	_	SpaceAfter=No
16	.	.	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 origin of a considerable proportion of the white sand upon certain tropical beaches |  |  |  |  | vn discover-84 «NP V NP»: agent=Agent origin=Topic |

<!-- .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 · ✓ the right answer {#o1}

<!-- .ven lang=en -->
Fragments of coral ground and excreted by parrotfish

```conllu
# sent_id = question:biology:172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams:e4:o1:1
# text = Fragments of coral ground and excreted by parrotfish
1	Fragments	fragment	NOUN	NNS	Number=Plur	6	nsubj:pass	_	_
2	of	of	ADP	IN	_	4	case	_	_
3	coral	coral	NOUN	NN	_	4	compound	_	_
4	ground	ground	NOUN	NN	Number=Sing	1	nmod	_	_
5	and	and	CCONJ	CC	_	6	cc	_	_
6	excreted	excrete	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	_	_
7	by	by	ADP	IN	_	8	case	_	_
8	parrotfish	parrotfish	NOUN	NN	Number=Sing	6	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **excrete** | participle · passive | parrotfish | Fragments of coral ground |  |  |  |  | tree rules |

### Option 2 {#o2}

<!-- .ven lang=en -->
Particles of salt deposited by evaporation of the sea

```conllu
# sent_id = question:biology:172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams:e4:o2:1
# text = Particles of salt deposited by evaporation of the sea
1	Particles	particle	NOUN	NNS	Number=Plur	0	root	_	_
2	of	of	ADP	IN	_	3	case	_	_
3	salt	salt	NOUN	NN	Number=Sing	1	nmod	_	_
4	deposited	deposit	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	1	acl	_	_
5	by	by	ADP	IN	_	6	case	_	_
6	evaporation	evaporation	NOUN	NN	Number=Sing	4	obl	_	_
7	of	of	ADP	IN	_	9	case	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	sea	sea	NOUN	NN	Number=Sing	6	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **deposit** | participle |  | Particles of salt *not said here* |  |  |  | by evaporation of the sea | vn put-9.1-1 «NP V NP PP.destination»: agent=Agent by evaporation=Destination |
| 2 | **evaporate** |  |  | the sea |  |  |  |  | nom evaporation «process transitive»: of=patient |

### Option 3 {#o3}

<!-- .ven lang=en -->
Shells of the giant clam crushed by waves

```conllu
# sent_id = question:biology:172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams:e4:o3:1
# text = Shells of the giant clam crushed by waves
1	Shells	shell	NOUN	NNS	Number=Plur	0	root	_	_
2	of	of	ADP	IN	_	5	case	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	5	det	_	_
4	giant	giant	ADJ	JJ	Degree=Pos	5	amod	_	_
5	clam	clam	NOUN	NN	Number=Sing	1	nmod	_	_
6	crushed	crush	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	5	acl	_	_
7	by	by	ADP	IN	_	8	case	_	_
8	waves	wave	NOUN	NNS	Number=Plur	6	obl:agent	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **crush** | participle |  | the giant clam *not said here* |  |  |  |  | vn carve-21.2-1 «NP V ADVP-Middle»: agent=Patient |

### Option 4 {#o4}

<!-- .ven lang=en -->
Pulverised volcanic glass of black colour

```conllu
# sent_id = question:biology:172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams:e4:o4:1
# text = Pulverised volcanic glass of black colour
1	Pulverised	pulveris	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	3	amod	_	_
2	volcanic	volcanic	ADJ	JJ	Degree=Pos	3	amod	_	_
3	glass	glass	NOUN	NN	Number=Sing	0	root	_	_
4	of	of	ADP	IN	_	6	case	_	_
5	black	black	ADJ	JJ	Degree=Pos	6	amod	_	_
6	colour	colour	NOUN	NN	Number=Sing	3	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **pulveris** | participle |  |  |  |  |  |  | tree rules |

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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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- ← previous: [Coral reef builders: polyps, bleaching…, exam 3](https://md.mova.elamur.ai/free/en/corpora/questions/biology/172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams/e3/)
- next →: [Coral reef partners and tricksters: cl…, test 1](https://md.mova.elamur.ai/free/en/corpora/questions/biology/173-coral-reef-partners-and-tricksters-clownfish-cleaners-mimics-and-puffers/t1/)
- ↑ back to [Coral reef builders: polyps, bleaching, sand from parrotfish and giant clams](https://md.mova.elamur.ai/free/en/corpora/questions/biology/172-coral-reef-builders-polyps-bleaching-sand-from-parrotfish-and-giant-clams/)