---
title: Ukraine's waters: Danube delta pelicans, Black Sea dolphins, sturgeo… — how Mova does on the tests · Biology
description: Lesson 374 of the biology course of Mova's primary school: 8 of 11 tests right, exam 2 of 4, every question with the options, the student's choice, the right answer and why it chose.
---

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# Ukraine's waters: Danube delta pelicans, Black Sea dolphins, sturgeon and gobies

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**Tests:** 8 of 11 right · **Exam:** 2 of 4 right · **Kind:** ★★ · **Understood:** 10 of 15 · **Run:** 2026-10-18, commit `f3c23ea72`

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Lesson 374 of the biology course of Mova's primary school, as Mova's small model took its tests: it had read this lesson and the ones before it and learned from their exercises. Each test shows the options in the order the student saw them, its choice, the right answer, the score of every option and why it chose. The lesson itself, sentence by sentence with trees and pragmatics: [the lesson in the corpora](https://md.mova.elamur.ai/free/en/corpora/school/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/).

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Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: [the lesson's questions in the corpora](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/).

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### Test 1 · ★★ · wrong ✗ {#t1}

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Count them: a pelican stands on both feet. How many webbed toes?

- **1.** 4 — **← Mova's choice** · no support
- **2.** 8 — **✓ the right answer** · no support
- **3.** 6 — no support
- **4.** 10 — no support

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**Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t1/)

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### Test 2 · ★★ · wrong ✗ {#t2}

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Count them: a sturgeon has 5 rows of bony plates and 4 whiskers. How many rows and whiskers together?

- **1.** 10 — **← Mova's choice** · no support
- **2.** 20 — no support
- **3.** 9 — **✓ the right answer** · no support
- **4.** 8 — no support

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**Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t2/)

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### Test 3 · ★★ · right ✓ {#t3}

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Count them: a boat crew sees one of each Black Sea kind of dolphin and porpoise. How many back fins altogether?

- **1.** 3 — **← Mova's choice** · **✓ the right answer** · no support
- **2.** 6 — no support
- **3.** 2 — no support
- **4.** 0 — no support

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**Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t3/)

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### Test 4 · ★★ · wrong ✗ {#t4}

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In Finding Nemo, Nigel the pelican flies off with fish held in his pouch full of water. What is right about real pelicans?

- **1.** They drain the water and swallow the fish, not fly about with a full pouch — **✓ the right answer** · score 6
- **2.** They carry fish for days to share with friends — score 3
- **3.** They keep the fish alive in the pouch as pets and let them swim around inside it — score 6
- **4.** They carry their eggs in the pouch — **← Mova's choice** · score 7

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**Why:** It took the question to ask which statement is true. It chose option 4 with score 7, against 6 for the next best. Its support: lesson 224, line 5: «And the Australian possum living in a roof is a different animal from the American opossum, though both carry their babies in pouches.», reached through the option's own match among the sentences about the question's things. What matched: the same place «pouches» (+4); the same thing acted on «babies» (+2); the same action «carry» (+1). The right option, 1, scored 6. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t4/)

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### Test 5 · ★★ · right ✓ {#t5}

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«it's a pelican, it can just take off like a sparrow» What is right?

- **1.** Pelicans jump straight up from the water — score 4
- **2.** Pelicans cannot fly at all — score 1
- **3.** Pelicans can only take off from the tops of tall trees by the river — score 1
- **4.** A heavy pelican runs along the water slapping its feet to take off — **← Mova's choice** · **✓ the right answer** · score 7

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**Why:** It took the question to ask which statement is true. It chose option 4 with score 7, against 4 for the next best. Its support: lesson 374, line 9: «A pelican has four toes on each foot, all joined by webbing, while a duck has three webbed toes and one free toe; pelicans take off by running along the water…», reached through a sentence linked to the one the question matched. What matched: the same action «run» (+3); the same doer «pelicans» (+2); the same place «water» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t5/)

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### Test 6 · ★★ · right ✓ {#t6}

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What would happen to the shipwrecks if worms could live deep in the Black Sea?

- **1.** The ships would turn to gold — score 7
- **2.** Nothing, because worms never eat wood — score 3
- **3.** The wood would be eaten and the ships would fall apart — **← Mova's choice** · **✓ the right answer** · score 10
- **4.** The ships would float back up to the surface by themselves — no support

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**Why:** It took the question to ask what happens next. It chose option 3 with score 10, against 7 for the next best. Its support: lesson 374, line 14: «Below about 150 to 200 metres the Black Sea has almost no oxygen and is full of a gas that smells of rotten eggs, and shipwrecks over 2,000 years old have been…», reached through what followed the sentence the question matched. What matched: the same action «eat» (+6); the same thing acted on «wood» (+3); the same doer «worms» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t6/)

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### Test 7 · ★★ · right ✓ {#t7}

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«dolphins died cos of the war, 100 percent, end of story» What is the careful answer?

- **1.** Dolphins died because the water got too cold — score -3
- **2.** Scientists think noise, fires and pollution may be part of it and still argue how much — **← Mova's choice** · **✓ the right answer** · score 6
- **3.** Scientists are certain it had nothing to do with it — no support
- **4.** Dolphins only die of old age — score -3

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**Why:** It took the question to ask which statement is true. It chose option 2 with score 6, against -3 for the next best. Its support: lesson 374, line 12: «After 2022 scientists counted many more dead dolphins than usual on Black Sea beaches; they think noise from warships, sonar (loud sound pulses ships send out…», reached through the option's own match among the sentences about the question's things. What matched: the same circumstance (+3); the same thing acted on «part» (+2); the same light verb (be, have, do, get, go) (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t7/)

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### Test 8 · ★★ · right ✓ {#t8}

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Why might fishing together work better for pelicans than fishing alone?

- **1.** Together they trap fish in shallow water where none can escape — **← Mova's choice** · **✓ the right answer** · score 1
- **2.** Alone they cannot open their big heavy bills wide enough to catch a fish — score 0
- **3.** Fish like to swim towards groups — no support
- **4.** Fishing alone is not allowed — no support

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**Why:** It took the question to ask why something happens (its cause). It chose option 1 with score 1, against 0 for the next best. Its support: lesson 374, line 7: «Great white pelicans fish as a team, driving fish into shallow water and dipping their heads at the same moment; the rare Dalmatian pelican, the biggest pelica…», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «fish» (+1); the same place «shallow water» (+1). Against it: a different action (counts against) (-1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t8/)

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### Test 9 · ★★ · right ✓ {#t9}

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«sturgeon been around since dinosaurs, so they'll be fine» Why are they in danger now?

- **1.** Their hard bony plates fall off when they get old, and they cannot grow new ones — no support
- **2.** Overfishing for their eggs and meat, and dams blocking their rivers — **← Mova's choice** · **✓ the right answer** · score 7
- **3.** They have forgotten how to swim — no support
- **4.** Dinosaurs still eat them — no support

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**Why:** It took the question to ask why something happens (its cause). It chose option 2 with score 7, the only option with support. Its support: lesson 374, line 15: «Sturgeons are ancient fish that have changed little since the age of dinosaurs; the beluga sturgeon can live over 100 years and grow longer than a car, but ove…», reached through the same lesson line as the sentence the question matched. What matched: the same action «overfish» (+5); the same circumstance (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t9/)

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### Test 10 · ★★ · right ✓ {#t10}

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«why do ships even carry water in tanks, that's dumb» What is right?

- **1.** Ships carry water to feed the gobies — score 2
- **2.** Ships carry water to wash all the fish that they catch out at sea — score 2
- **3.** Ships carry water so the crew can make tea all day long — score 1
- **4.** Ships carry water in tanks to keep steady when they are light — **← Mova's choice** · **✓ the right answer** · score 9

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**Why:** It took the question to ask why something happens (its cause). It chose option 4 with score 9, against 2 for the next best. Its support: lesson 374, line 18: «Ships carry water in tanks to keep steady when lightly loaded, and round gobies travelled in these tanks to faraway ports and spread into the Great Lakes of No…», reached through the cause of the sentence the question matched. What matched: the same action «keep» (+4); the same property (+4); the same doer «ships» (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t10/)

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### Test 11 · ★★ · right ✓ {#t11}

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What would happen if a river stopped carrying mud to its mouth?

- **1.** The delta would stop building new land into the sea — **← Mova's choice** · **✓ the right answer** · score 7
- **2.** The sea around it would slowly turn into fresh water — no support
- **3.** The delta would grow faster than ever before — no support
- **4.** The river would flow uphill — score 1

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**Why:** It took the question to ask what happens next. It chose option 1 with score 7, against 1 for the next best. Its support: lesson 374, line 1: «In Ukraine's south-west a boat slides through channels of tall reeds where the Danube meets the Black Sea. Mud carried by the great river piles up at its mouth…», reached through the same lesson line as the sentence the question matched. What matched: the same thing acted on «new land» (+3); the same action «build» (+2); the same doer «delta» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/t11/)

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### Exam question 1 · formal language · right ✓ {#e1}

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Identify the principal reason for which the Ukrainian portion of the Danube delta extends further into the sea with each year.

- **1.** Sediment transported by the river is deposited at its mouth — **← Mova's choice** · **✓ the right answer** · no support
- **2.** Reeds displace sea water by their growth — no support
- **3.** Sand is deposited there by human labour — no support
- **4.** The level of the Black Sea is falling rapidly — no support

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**Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/e1/)

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### Exam question 2 · formal language · right ✓ {#e2}

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Select the response consistent with the established facts concerning the feeding of the pelican.

- **1.** The pouch serves exclusively for the storage of eggs — no support
- **2.** Fish are transported for long distances within the water-filled pouch — score 6
- **3.** Water is drained from the pouch before the fish are swallowed — **← Mova's choice** · **✓ the right answer** · score 9
- **4.** Fish are caught with the feet — no support

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**Why:** It took the question to ask which statement is true. It chose option 3 with score 9, against 6 for the next best. Its support: lesson 134, line 14: «Pelicans scoop fish and water into their throat pouch, then tip their heads to drain the water before swallowing; a brown pelican's pouch holds about 11 litres…», reached through the option's own match among the sentences about the question's things. What matched: the same place «throat pouch» (+4); the same circumstance (+3); the same thing acted on «fish» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/e2/)

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### Exam question 3 · formal language · wrong ✗ {#e3}

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Which of the following statements most accurately characterises the deep waters of the Black Sea below approximately two hundred metres?

- **1.** They are almost devoid of oxygen, and few organisms besides bacteria inhabit them — **✓ the right answer** · score 1
- **2.** They are inhabited principally by dolphins, porpoises and the larger sturgeon — score 3
- **3.** They are richer in oxygen than the surface — no support
- **4.** They are frozen throughout the year — **← Mova's choice** · score 5

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**Why:** It took the question to ask who or what does it. It chose option 4 with score 5, against 3 for the next best. Its support: lesson 131, line 16: «In the Ice Age so much water was frozen into ice sheets that the sea was much lower, and people could walk from Asia to America over land that is now under the…», reached through the option's own match among the sentences about the question's things. What matched: the same action «freeze» (+3); the same thing acted on «much water» (+2). The right option, 1, scored 1. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/e3/)

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### Exam question 4 · formal language · wrong ✗ {#e4}

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Ascertain the manner in which the round goby was conveyed from the Black Sea to the Great Lakes of North America.

- **1.** By migration across the Atlantic Ocean — **← Mova's choice** · no support
- **2.** In water held in the tanks of ships — **✓ the right answer** · no support
- **3.** Upon the feet and feathers of migrating birds — no support
- **4.** By deliberate stocking for sport fishing — no support

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**Why:** No option found support in what it remembers, so it guessed: it took the first option shown. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/biology/374-ukraine-s-waters-danube-delta-pelicans-black-sea-dolphins-sturgeon-and-gobies/e4/)

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