Exam question 2 · Balance in a food web

Identify the principal reason for which predators are invariably fewer than plant-eaters.

Mova's choice: option 3 · The right answer: option 3 · right ✓ · Who acts: you, predators · What happens: identify, be · To what, where: principal reason

This is exam question 2 of lesson 30 «Balance in a food web» of the world 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	7 predators	det
7	predators	predator	NOUN	Number=Plur	10 fewer	nsubj
8	are	be	AUX	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	10 fewer	cop
9	invariably	invariably	ADV	_	10 fewer	advmod
10	fewer	few	ADJ	Degree=Cmp	4 reason	nmod
11	than	than	ADP	_	14 eaters	case
12	plant	plant	NOUN	Number=Sing	14 eaters	compound
13	-	-	PUNCT	_	12 plant	punct
14	eaters	eater	NOUN	Number=Plur	10 fewer	obl
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 predators					than plant eaters; few, invariably 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

Plants are fewer than predators

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Plants	plant	NOUN	Number=Plur	3 fewer	nsubj
2	are	be	AUX	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	3 fewer	cop
3	fewer	few	ADJ	Degree=Cmp	root	root
4	than	than	ADP	_	5 predators	case
5	predators	predator	NOUN	Number=Plur	3 fewer	obl

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	is	present	Plants					than predators; few property	tree rules

Option 2

Predators are hunted by plant-eaters

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Predators	predator	NOUN	Number=Plur	3 hunted	nsubj
2	are	be	AUX	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	3 hunted	aux:pass
3	hunted	hunt	VERB	Tense=Past VerbForm=Part Voice=Pass	root	root
4	by	by	ADP	_	7 eaters	case
5	plant	plant	NOUN	Number=Sing	7 eaters	compound
6	-	-	PUNCT	_	5 plant	punct
7	eaters	eater	NOUN	Number=Plur	3 hunted	obl

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	hunt	present · passive	plant eaters	Predators					vn hunt-35.1 «NP V NP»: agent=Agent subject=Theme

Option 3 · ← Mova's choice · ✓ the right answer

Energy is lost at each step of the food chain

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Energy	energy	NOUN	Number=Sing	3 lost	nsubj:pass
2	is	be	AUX	Mood=Ind Number=Sing Person=3 Tense=Pres VerbForm=Fin	3 lost	aux:pass
3	lost	lose	VERB	Tense=Past VerbForm=Part Voice=Pass	root	root
4	at	at	ADP	_	6 step	case
5	each	each	DET	PronType=Tot	6 step	det
6	step	step	NOUN	Number=Sing	3 lost	obl
7	of	of	ADP	_	10 chain	case
8	the	the	DET	Definite=Def PronType=Art	10 chain	det
9	food	food	NOUN	Number=Sing	10 chain	compound
10	chain	chain	NOUN	Number=Sing	6 step	nmod

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	lose	present · passive		Energy				at each step of the food chain	vn succeed-74-3-1 «NP V NP»: subject=Eventuality
2	step			the food chain					nom step «act transitive»: of=patient

Option 4

Predators reproduce more slowly from choice

The words, one row each (CoNLL-U)

#	word	lemma	UPOS	features	head	relation
1	Predators	predator	NOUN	Number=Plur	2 reproduce	nsubj
2	reproduce	reproduce	VERB	Mood=Ind Number=Plur Person=3 Tense=Pres VerbForm=Fin	root	root
3	more	more	ADV	Degree=Cmp	4 slowly	advmod
4	slowly	slowly	ADV	_	2 reproduce	advmod
5	from	from	ADP	_	6 choice	case
6	choice	choice	NOUN	Number=Sing	2 reproduce	obl

#	verb	tense, mood	who	what, whom	to whom	where	when	other	roles by
1	reproduce	present	Predators			choice		slowly property	vn birth-28.2-2 «NP V»: agent=Agent

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.

This page in Markdown → https://md.mova.elamur.ai/free/en/corpora/questions/world/30-balance-in-food-webs/e2/