Exam question 2 · Food chains: sun, plants, plant-eaters, meat-eaters

Identify the principal reason for which food chains are seldom longer than five steps.

Mova's choice: option 1 · The right answer: option 1 · right ✓ · Who acts: you, food chains · What happens: identify, be · To what, where: principal reason

This is exam question 2 of lesson 46 «Food chains: sun, plants, plant-eaters, meat-eaters» 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.

The question

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Identify	identify	VERB	Mood=Imp VerbForm=Fin	root	root
2	the	the	DET	Definite=Def PronType=Art	4 reason	det
3	principal	principal	ADJ	Degree=Pos	4 reason	amod
4	reason	reason	NOUN	Number=Sing	1 Identify	obj
5	for	for	ADP	_	6 which	case
6	which	which	DET	PronType=Int	8 chains	det
7	food	food	NOUN	Number=Sing	8 chains	compound
8	chains	chain	NOUN	Number=Plur	14 steps	nsubj
9	are	be	AUX	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	14 steps	cop
10	seldom	seldom	ADV	_	11 longer	advmod
11	longer	long	ADV	Degree=Cmp	14 steps	advmod
12	than	than	ADP	_	14 steps	case
13	five	five	NUM	NumForm=Word NumType=Card	14 steps	nummod
14	steps	step	NOUN	Number=Plur	4 reason	nmod
15	.	.	PUNCT	_	1 Identify	punct

#	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	is	present	which food chains					than five steps; long property	tree rules

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

Option 1 · ← Mova's choice · ✓ the right answer

At each step most energy is expended, so too little remains for further steps

The tree, 14 words

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	At	at	ADP	_	3 step	case
2	each	each	DET	PronType=Tot	3 step	det
3	step	step	NOUN	Number=Sing	7 expended	obl
4	most	most	ADJ	Degree=Sup	5 energy	amod
5	energy	energy	NOUN	Number=Sing	7 expended	nsubj:pass
6	is	be	AUX	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	7 expended	aux:pass
7	expended	expend	VERB	Tense=Past VerbForm=Part Voice=Pass	root	root
8	,	,	PUNCT	_	12 remains	punct
9	so	so	ADV	_	12 remains	advmod
10	too	too	ADV	_	11 little	advmod
11	little	little	ADJ	Degree=Pos	12 remains	amod
12	remains	remains	NOUN	Number=Ptan	7 expended	obl
13	for	for	ADP	_	15 steps	case
14	further	further	ADJ	Degree=Pos	15 steps	amod
15	steps	step	NOUN	Number=Plur	7 expended	obl

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	expend	present · passive		most energy				at each step; for further steps; little remains obl	tree rules

Option 2

Plants cease to grow when a chain exceeds five steps

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Plants	plant	NOUN	Number=Plur	2 cease	nsubj
2	cease	cease	VERB	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	root	root
3	to	to	PART	_	4 grow	mark
4	grow	grow	VERB	VerbForm=Inf	2 cease	xcomp
5	when	when	SCONJ	_	8 exceeds	mark
6	a	a	DET	Definite=Ind PronType=Art	7 chain	det
7	chain	chain	NOUN	Number=Sing	8 exceeds	nsubj
8	exceeds	exceed	VERB	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	4 grow	advcl
9	five	five	NUM	NumForm=Word NumType=Card	10 steps	nummod
10	steps	step	NOUN	Number=Plur	8 exceeds	obj

#	verb	tense, mood	who	what, whom	roles by
1	cease	present	Plants		vn stop-55.4-1-1 «NP V S_ING»: agent=Affector clause=Eventuality
2	grow	to-infinitive	Plants not said here		vn appear-48.1.1 «NP V»: agent=Theme
3	exceed	present	a chain	five steps	vn exceed-90 «NP V NP»: agent=Pivot step=Theme

Option 3

Predators are prohibited by their nature from consuming other predators

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Predators	predator	NOUN	Number=Plur	3 prohibited	nsubj:pass
2	are	be	AUX	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	3 prohibited	aux:pass
3	prohibited	prohibit	VERB	Tense=Past VerbForm=Part Voice=Pass	root	root
4	by	by	ADP	_	6 nature	case
5	their	their	PRON	Case=Gen Number=Plur Person=3 Poss=Yes PronType=Prs	6 nature	nmod:poss
6	nature	nature	NOUN	Number=Sing	3 prohibited	obl
7	from	from	SCONJ	_	8 consuming	mark
8	consuming	consume	VERB	Tense=Pres VerbForm=Part	3 prohibited	advcl
9	other	other	ADJ	Degree=Pos	10 predators	amod
10	predators	predator	NOUN	Number=Plur	8 consuming	obj

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	prohibit	present · passive	Predators's nature	Predators					vn forbid-64.4-1 «NP V NP»: agent=Causer subject=Theme
2	consume	gerund	Predators's nature not said here	other predators					vn consume-66 «NP V NP»: agent=Agent predator=Asset

Option 4

Animals at the summit of a chain require no food

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Animals	animal	NOUN	Number=Plur	8 require	nsubj
2	at	at	ADP	_	4 summit	case
3	the	the	DET	Definite=Def PronType=Art	4 summit	det
4	summit	summit	NOUN	Number=Sing	1 Animals	nmod
5	of	of	ADP	_	7 chain	case
6	a	a	DET	Definite=Ind PronType=Art	7 chain	det
7	chain	chain	NOUN	Number=Sing	4 summit	nmod
8	require	require	VERB	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	root	root
9	no	no	DET	PronType=Neg	10 food	det
10	food	food	NOUN	Number=Sing	8 require	obj

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	require	present	Animals at the summit of a chain	no food					vn require-103-1 «NP V NP»: agent=Theme food=Precondition

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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