---
title: Identify the principal reason for which the head of the pigeon appea… — Pigeons: head bobbing, homing and city… · tree and pragmatics
description: Identify the principal reason for which the head of the pigeon appears to move rhythmically during locomotion. Exam question 1 of lesson 221 «Pigeons: head bobbing, homing and city cliffs» of the biology course of Mova's primary school, with the dependency tree and pragmatics of the question and of 
---

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# Exam question 1 · Pigeons: head bobbing, homing and city cliffs

<!-- .ven lang=en -->
Identify the principal reason for which the head of the pigeon appears to move rhythmically during locomotion.

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

<!-- .vabout -->
This is exam question 1 of lesson 221 «Pigeons: head bobbing, homing and city cliffs» 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/221-pigeons-head-bobbing-homing-and-city-cliffs/#e1).

## The question {#question}

```conllu
# sent_id = question:biology:221-pigeons-head-bobbing-homing-and-city-cliffs:e1:1
# text = Identify the principal reason for which the head of the pigeon appears to move rhythmically during locomotion.
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	reason	reason	NOUN	NN	Number=Sing	1	obj	_	_
5	for	for	ADP	IN	_	6	case	_	_
6	which	which	PRON	WDT	PronType=Rel	12	obl	_	_
7	the	the	DET	DT	Definite=Def|PronType=Art	8	det	_	_
8	head	head	NOUN	NN	Number=Sing	12	nsubj	_	_
9	of	of	ADP	IN	_	11	case	_	_
10	the	the	DET	DT	Definite=Def|PronType=Art	11	det	_	_
11	pigeon	pigeon	NOUN	NN	Number=Sing	8	nmod	_	_
12	appears	appear	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	acl	_	_
13	to	to	PART	TO	_	14	mark	_	_
14	move	move	VERB	VB	VerbForm=Inf	12	xcomp	_	_
15	rhythmically	rhythmically	ADV	RB	_	14	advmod	_	_
16	during	during	ADP	IN	_	17	case	_	_
17	locomotion	locomotion	NOUN	NN	Number=Sing	14	obl	_	SpaceAfter=No
18	.	.	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 reason |  |  |  |  | vn characterize-29.2-1-1 «NP V NP S\_ING»: agent=Agent reason=Theme |
| 2 | **appear** | present | the head of the pigeon |  |  |  |  | for the principal reason | vn seem-109-1-1-1 «NP V S\_INF»: agent=Theme clause=Attribute |
| 3 | **move** | to-infinitive | the head of the pigeon *not said here* |  |  |  | during locomotion | rhythmically *property* | vn roll-51.3.1 «NP.theme V»: 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 -->
The head is held stationary during each step, thereby stabilising the visual field

```conllu
# sent_id = question:biology:221-pigeons-head-bobbing-homing-and-city-cliffs:e1:o1:1
# text = The head is held stationary during each step, thereby stabilising the visual field
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	head	head	NOUN	NN	Number=Sing	4	nsubj:pass	_	_
3	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	aux:pass	_	_
4	held	hold	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	_	_
5	stationary	stationary	NOUN	NN	Number=Sing	4	obj	_	_
6	during	during	ADP	IN	_	8	case	_	_
7	each	each	DET	DT	PronType=Tot	8	det	_	_
8	step	step	NOUN	NN	Number=Sing	4	obl	_	SpaceAfter=No
9	,	,	PUNCT	,	_	11	punct	_	_
10	thereby	thereby	ADV	RB	_	11	advmod	_	_
11	stabilising	stabilise	VERB	VBG	Tense=Pres|VerbForm=Part	4	advcl	_	_
12	the	the	DET	DT	Definite=Def|PronType=Art	14	det	_	_
13	visual	visual	ADJ	JJ	Degree=Pos	14	amod	_	_
14	field	field	NOUN	NN	Number=Sing	11	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **hold** | present · passive |  | the head |  |  | during each step |  | vn conjecture-29.5 «NP V NP to be NP»: subject=Theme stationary=Eventuality |
| 2 | **stabilise** | gerund |  | the visual field |  |  |  | thereby *property* | tree rules |

### Option 2 {#o2}

<!-- .ven lang=en -->
The movement constitutes a response to audible rhythm

```conllu
# sent_id = question:biology:221-pigeons-head-bobbing-homing-and-city-cliffs:e1:o2:1
# text = The movement constitutes a response to audible rhythm
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	movement	movement	NOUN	NN	Number=Sing	3	nsubj	_	_
3	constitutes	constitute	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
4	a	a	DET	DT	Definite=Ind|PronType=Art	5	det	_	_
5	response	response	NOUN	NN	Number=Sing	3	obj	_	_
6	to	to	ADP	IN	_	8	case	_	_
7	audible	audible	ADJ	JJ	Degree=Pos	8	amod	_	_
8	rhythm	rhythm	NOUN	NN	Number=Sing	5	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **constitute** | present | the movement | a response |  |  |  | to audible rhythm | vn comprise-107.2-1 «NP V NP»: agent=Theme response=Pivot |

### Option 3 {#o3}

<!-- .ven lang=en -->
The movement results from a deficiency in the musculature of the neck, common to all pigeons

<!-- fold The tree, 16 words -->
```conllu
# sent_id = question:biology:221-pigeons-head-bobbing-homing-and-city-cliffs:e1:o3:1
# text = The movement results from a deficiency in the musculature of the neck, common to all pigeons
1	The	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
2	movement	movement	NOUN	NN	Number=Sing	3	compound	_	_
3	results	result	NOUN	NNS	Number=Plur	14	nsubj	_	_
4	from	from	ADP	IN	_	6	case	_	_
5	a	a	DET	DT	Definite=Ind|PronType=Art	6	det	_	_
6	deficiency	deficiency	NOUN	NN	Number=Sing	3	nmod	_	_
7	in	in	ADP	IN	_	9	case	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	musculature	musculature	NOUN	NN	Number=Sing	6	nmod	_	_
10	of	of	ADP	IN	_	12	case	_	_
11	the	the	DET	DT	Definite=Def|PronType=Art	12	det	_	_
12	neck	neck	NOUN	NN	Number=Sing	9	nmod	_	SpaceAfter=No
13	,	,	PUNCT	,	_	14	punct	_	_
14	common	common	ADJ	JJ	Degree=Pos	0	root	_	_
15	to	to	ADP	IN	_	17	case	_	_
16	all	all	DET	DT	PronType=Tot	17	det	_	_
17	pigeons	pigeon	NOUN	NNS	Number=Plur	14	obl	_	_
```

<!-- .note -->
The frames reader finds no event or fact in this sentence.

### Option 4 {#o4}

<!-- .ven lang=en -->
The head is propelled forward to assist the motion of the body

```conllu
# sent_id = question:biology:221-pigeons-head-bobbing-homing-and-city-cliffs:e1:o4:1
# text = The head is propelled forward to assist the motion of the body
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	head	head	NOUN	NN	Number=Sing	4	nsubj:pass	_	_
3	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	aux:pass	_	_
4	propelled	propel	VERB	VBN	Tense=Past|VerbForm=Part|Voice=Pass	0	root	_	_
5	forward	forward	ADV	RB	_	4	advmod	_	_
6	to	to	PART	TO	_	7	mark	_	_
7	assist	assist	VERB	VB	VerbForm=Inf	4	advcl	_	_
8	the	the	DET	DT	Definite=Def|PronType=Art	9	det	_	_
9	motion	motion	NOUN	NN	Number=Sing	7	obj	_	_
10	of	of	ADP	IN	_	12	case	_	_
11	the	the	DET	DT	Definite=Def|PronType=Art	12	det	_	_
12	body	body	NOUN	NN	Number=Sing	9	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **propel** | present · passive |  | the head |  |  |  | forward *property* | tree rules |
| 2 | **assist** | to-infinitive |  | the motion of the body |  |  |  |  | vn help-72.1-1-1 «NP V NP»: agent=Agent motion=Beneficiary |
| 3 | **motion** |  | the body |  |  |  |  |  | nom motion «communication 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.

<!-- /div -->

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