---
title: Identify the principal function of the hooked barbules of a feather. — Birds: feathers, wings, eggs and flight · tree and pragmatics
description: Identify the principal function of the hooked barbules of a feather. Exam question 1 of lesson 33 «Birds: feathers, wings, eggs and flight» 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 1 · Birds: feathers, wings, eggs and flight

<!-- .ven lang=en -->
Identify the principal function of the hooked barbules of a feather.

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

<!-- .vabout -->
This is exam question 1 of lesson 33 «Birds: feathers, wings, eggs and flight» 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/33-birds-feathers-wings-eggs-and-flight/#e1).

## The question {#question}

```conllu
# sent_id = question:biology:33-birds-feathers-wings-eggs-and-flight:e1:1
# text = Identify the principal function of the hooked barbules of a feather.
1	Identify	identify	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
3	principal	principal	ADJ	JJ	Degree=Pos	4	amod	_	_
4	function	function	NOUN	NN	Number=Sing	1	obj	_	_
5	of	of	ADP	IN	_	8	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
7	hooked	hook	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	8	amod	_	_
8	barbules	barbule	NOUN	NNS	Number=Plur	4	nmod	_	_
9	of	of	ADP	IN	_	11	case	_	_
10	a	a	DET	DT	Definite=Ind|PronType=Art	11	det	_	_
11	feather	feather	NOUN	NN	Number=Sing	8	nmod	_	SpaceAfter=No
12	.	.	PUNCT	.	_	1	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **identify** | imperative | you *not said here* | the principal function of the hooked barbules of a feather |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent function=Theme |
| 2 | **hook** | participle |  |  |  |  |  |  | vn coil-9.6-1 «NP V ADV-Middle»: agent=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.

## The options {#options}

### Option 1 · ← Mova's choice · ✓ the right answer {#o1}

<!-- .ven lang=en -->
To interlock the barbs into a continuous surface

```conllu
# sent_id = question:biology:33-birds-feathers-wings-eggs-and-flight:e1:o1:1
# text = To interlock the barbs into a continuous surface
1	To	to	PART	TO	_	2	mark	_	_
2	interlock	interlock	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	barbs	barb	NOUN	NNS	Number=Plur	2	obj	_	_
5	into	into	ADP	IN	_	8	case	_	_
6	a	a	DET	DT	Definite=Ind|PronType=Art	8	det	_	_
7	continuous	continuous	ADJ	JJ	Degree=Pos	8	amod	_	_
8	surface	surface	NOUN	NN	Number=Sing	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **interlock** | to-infinitive |  | the barbs |  | a continuous surface |  |  | vn amalgamate-22.2-2-1 «NP V NP»: agent=Agent barb=Patient |

### Option 2 {#o2}

<!-- .ven lang=en -->
To anchor the feather within the skin

```conllu
# sent_id = question:biology:33-birds-feathers-wings-eggs-and-flight:e1:o2:1
# text = To anchor the feather within the skin
1	To	to	PART	TO	_	2	mark	_	_
2	anchor	anchor	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
3	the	the	DET	DT	Definite=Def|PronType=Art	4	det	_	_
4	feather	feather	NOUN	NN	Number=Sing	2	obj	_	_
5	within	within	ADP	IN	_	7	case	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	skin	skin	NOUN	NN	Number=Sing	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **anchor** | to-infinitive |  | the feather |  |  |  | within the skin | vn tape-22.4 «NP V NP»: agent=Agent feather=Patient |

### Option 3 {#o3}

<!-- .ven lang=en -->
To store oil for waterproofing

```conllu
# sent_id = question:biology:33-birds-feathers-wings-eggs-and-flight:e1:o3:1
# text = To store oil for waterproofing
1	To	to	PART	TO	_	2	mark	_	_
2	store	store	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
3	oil	oil	NOUN	NN	Number=Sing	2	obj	_	_
4	for	for	ADP	IN	_	5	case	_	_
5	waterproofing	waterproofing	NOUN	NN	Number=Sing	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **store** | to-infinitive |  | oil |  |  |  | for waterproofing | vn keep-15.2 «NP V NP»: agent=Agent oil=Theme |

### Option 4 {#o4}

<!-- .ven lang=en -->
To sense vibrations of the air during flight

```conllu
# sent_id = question:biology:33-birds-feathers-wings-eggs-and-flight:e1:o4:1
# text = To sense vibrations of the air during flight
1	To	to	PART	TO	_	2	mark	_	_
2	sense	sense	VERB	VB	Mood=Imp|VerbForm=Fin	0	root	_	_
3	vibrations	vibration	NOUN	NNS	Number=Plur	2	obj	_	_
4	of	of	ADP	IN	_	6	case	_	_
5	the	the	DET	DT	Definite=Def|PronType=Art	6	det	_	_
6	air	air	NOUN	NN	Number=Sing	3	nmod	_	_
7	during	during	ADP	IN	_	8	case	_	_
8	flight	flight	NOUN	NN	Number=Sing	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **sense** | to-infinitive |  | vibrations of the air |  |  | during flight |  | vn see-30.1-1 «NP V S»: agent=Experiencer vibration=Stimulus |
| 2 | **vibrate** |  | the air |  |  |  |  |  | nom vibration «act intransitive»: of=agent |

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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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