The Arctic Ocean: walruses, bowheads, the 400-year shark and the unicorn's tooth
Tests: 8 of 12 right · Exam: 1 of 4 right · Kind: ★★ · Understood: 10 of 16 · Run: 2026-10-18, commit f3c23ea72
Lesson 169 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.
Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: the lesson's questions in the corpora.
Test 1 · ★★ · right ✓
«got a unicorn horn in grandpa's attic, worth millions» What is it most likely?
- 1. A narwhal tusk, which is really a whale's tooth — ← Mova's choice · ✓ the right answer · no support
- 2. A walrus whisker — no support
- 3. A real unicorn's horn — no support
- 4. A goat's horn painted white — no support
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
Test 2 · ★★ · right ✓
«polar bears are white all the way through, duh» What is right?
- 1. Their skin is white and their hairs are black underneath — no support
- 2. Yes, white skin and white hair — no support
- 3. They are grey under the fur — no support
- 4. Their skin is black and their hairs are see-through — ← Mova's choice · ✓ the right answer · score 7
Why: It took the question to ask which statement is true. It chose option 4 with score 7, the only option with support. Its support: lesson 6, line 6: «Polar bears hunt seals from the sea ice and swim well, kept warm by fat up to about 10 cm thick; their skin is black and their hairs are see-through, only look…», reached through the same lesson line as the sentence the question matched. What matched: the same doer «skin» (+3); the same property (+3); the same light verb (be, have, do, get, go) (+1). · the question and its options parsed, with trees and pragmatics
Test 3 · ★★ · right ✓
«3 walruses on the ice, how many tusks»
- 1. 6 — ← Mova's choice · ✓ the right answer · no support
- 2. 9 — no support
- 3. 12 — no support
- 4. 3 — no support
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
Test 4 · ★★ · right ✓
«2 narwhal boys, one tusk each, n a walrus, how many tusks altogether»
- 1. 4 — ← Mova's choice · ✓ the right answer · no support
- 2. 3 — no support
- 3. 2 — no support
- 4. 6 — no support
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
Test 5 · ★★ · right ✓
What would happen to polar bears if the sea ice melted much earlier each year?
- 1. They would have less time to hunt seals from the ice and swim longer — ← Mova's choice · ✓ the right answer · score 10
- 2. They would move to Antarctica and hunt penguins instead of seals — score 8
- 3. They would get fatter — no support
- 4. Nothing at all — no support
Why: It took the question to ask what happens next. It chose option 1 with score 10, against 8 for the next best. Its support: lesson 105, line 9: «Arctic sea ice now melts earlier and freezes later as the climate warms, so polar bears have less time to hunt seals, though they can go months without eating…», reached through the same lesson line as the sentence the question matched. What matched: the same action «hunt» (+4); the same doer «polar bears» (+3); the same thing acted on «seals» (+3). · the question and its options parsed, with trees and pragmatics
Test 6 · ★★ · wrong ✗
«that shark's 400?? no way, they're just guessing» What is right?
- 1. It is a guess with no evidence — no support
- 2. They counted its birthdays — no support
- 3. Sharks live only ten years — ← Mova's choice · score 8
- 4. Scientists measured it with a carbon clock in its eye lens, though the age is only an estimate — ✓ the right answer · score 8
Why: It took the question to ask which statement is true. It chose option 3 with score 8, tied with another option at 8 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 169, line 3: «Under the ice swim some of the oldest animals on Earth: bowhead whales that may live over two hundred years and Greenland sharks that may live about four hundr…», reached through the same lesson line as the sentence the question matched. What matched: the same action «live» (+5); the same property (+3). The right option, 4, scored 8. · the question and its options parsed, with trees and pragmatics
Test 7 · ★★ · right ✓
In a cartoon a beluga talks in words like a person. What is real?
- 1. Belugas only bark like dogs — no support
- 2. Belugas make no sounds at all, they are the silent whales — score 1
- 3. Real belugas whistle, click and chirp but do not speak words — ← Mova's choice · ✓ the right answer · score 5
- 4. Belugas speak English — no support
Why: It took the question to ask which statement is true. It chose option 3 with score 5, against 1 for the next best. Its support: lesson 17, line 15: «Apes cannot speak words like us because their throat, tongue and breathing control are different, but the bonobo Kanzi learned hundreds of symbols, first by wa…», reached through the remembered sentence the question matched. What matched: the same thing acted on «words» (+4); the same action «speak» (+1). · the question and its options parsed, with trees and pragmatics
Test 8 · ★★ · wrong ✗
«a whale with a harpoon from like 1880 in it, it's a fake story» What is right?
- 1. It was a shark, not a whale — score 3
- 2. It is fake, because whales only ever live about twenty years — ← Mova's choice · score 5
- 3. It is true: bowheads can live over two hundred years — ✓ the right answer · score 5
- 4. The harpoon was put in last year — no support
Why: It took the question to ask which statement is true. It chose option 2 with score 5, tied with another option at 5 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 169, line 7: «Bowhead whales can smash through ice with their heads to make breathing holes, and they may live for over two hundred years; old harpoon tips from the 1800s ha…», reached through the option's own match among the sentences about the question's things. What matched: the same property (+3); the same action «live» (+2). The right option, 3, scored 5. · the question and its options parsed, with trees and pragmatics
Test 9 · ★★ · wrong ✗
«the arctic's dead in winter, nothing moves in the dark» What did scientists find?
- 1. The sea turns to rock — ← Mova's choice · no support
- 2. Everything freezes solid — no support
- 3. Only polar bears are awake, and every sea animal sleeps until spring — no support
- 4. Tiny sea animals still move up and down in the dark water — ✓ the right answer · no support
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
Test 10 · ★★ · wrong ✗
A bird ringed in Greenland is seen next summer near Antarctica. Which bird is most likely?
- 1. A ptarmigan of the tundra — ← Mova's choice · score 5
- 2. An arctic tern — ✓ the right answer · score 4
- 3. A white snowy owl — no support
- 4. A penguin flying north — no support
Why: It took the question to ask who or what does it. It chose option 1 with score 5, against 4 for the next best. Its support: lesson 168, line 16: «Ptarmigans are birds that turn white in winter and brown in summer, and they dig snow caves to sleep in because snow keeps the warmth in.», reached through the remembered sentence the question matched. What matched: the same light verb (be, have, do, get, go) (+3); it fills the role the question asks for (+2). The right option, 2, scored 4. · the question and its options parsed, with trees and pragmatics
Test 11 · ★★ · right ✓
Why does a harp seal pup need milk that is about half fat?
- 1. To make its fur white — no support
- 2. To stop it from growing too big for the den — no support
- 3. To grow fast and build blubber before it must swim in icy water — ← Mova's choice · ✓ the right answer · score 9
- 4. Because seals cannot drink water — no support
Why: It took the question to ask why something happens (its cause). It chose option 3 with score 9, the only option with support. Its support: lesson 169, line 15: «Harp seal pups are born white on the ice, turn grey after a few weeks, and grow very fast on milk that is about half fat, building a thick layer of fat called…», reached through the same lesson line as the sentence the question matched. What matched: the same action «swim» (+4); the same place «icy water» (+4); a different doer (counts against) (+1). · the question and its options parsed, with trees and pragmatics
Test 12 · ★★ · right ✓
«why do walruses have whiskers, they're not cats lol» What is right?
- 1. To keep their noses warm in the freezing water — score 10
- 2. To scare off polar bears — score 5
- 3. They feel for clams on the dark seabed — ← Mova's choice · ✓ the right answer · score 12
- 4. To look like cats — score 6
Why: It took the question to ask why something happens (its cause). It chose option 3 with score 12, against 10 for the next best. Its support: lesson 169, line 6: «Walruses find clams on the dark seabed with hundreds of sensitive whiskers and suck them out of their shells.», reached through the same lesson line as the sentence the question matched. What matched: the same action «find» (+4); the same place «dark seabed» (+4); the same doer «walruses» (+2); the same circumstance (+2). · the question and its options parsed, with trees and pragmatics
Exam question 1 · formal language · wrong ✗
Identify the principal method by which the age of the Greenland shark has been estimated.
- 1. The testimony of fishermen — no support
- 2. The analysis of a radiocarbon record contained within the lens of the eye — ✓ the right answer · no support
- 3. The measurement of its weight — no support
- 4. The enumeration of the rings within its teeth — ← Mova's choice · score 5
Why: It took the question to ask which statement is true. It chose option 4 with score 5, the only option with support. Its support: lesson 87, line 14: «A rattlesnake's rattle is made of hollow rings of hard skin; a ring is added at each shed, several times a year, and old rings break off, so you cannot tell it…», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «rings» (+3); the same action «count» (+2). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics
Exam question 2 · formal language · wrong ✗
Select the response consistent with the established facts concerning the colouration of the polar bear.
- 1. The skin and hairs alike are pigmented white — ← Mova's choice · no support
- 2. The skin is black and the translucent hollow hairs appear white by scattering light — ✓ the right answer · no support
- 3. The animal is grey beneath a layer of snow — no support
- 4. The skin is white and the hairs are pigmented black — no support
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
Exam question 3 · formal language · wrong ✗
Which of the following statements most accurately characterises the so-called unicorn horns traded in medieval Europe?
- 1. They were fashioned from walrus whiskers — ← Mova's choice · score 7
- 2. They were the antlers of reindeer — score 7
- 3. They were the horns of a now extinct horse of the northern forests — score 7
- 4. They were in fact the spiral tusks of the narwhal, which are teeth — ✓ the right answer · score 7
Why: It took the question to ask who or what does it. It chose option 1 with score 7, tied with another option at 7 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 167, line 16: «Tasmania's mountain ash trees are among the tallest flowering trees in the world, and the one called the Centurion is about a hundred metres tall, as tall as a…», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+4); the same doer «one» (+3). The right option, 4, scored 7. · the question and its options parsed, with trees and pragmatics
Exam question 4 · formal language · right ✓
Ascertain the principal consequence for the polar bear of the progressive diminution of Arctic sea ice.
- 1. A reduction in the time available for hunting seals from the ice and longer distances to be swum — ← Mova's choice · ✓ the right answer · no support
- 2. The adoption of a diet of plants exclusively — no support
- 3. A migration of the species to Antarctica — no support
- 4. An increase in body weight — no support
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
This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/biology/169-the-arctic-ocean-walruses-bowheads-the-400-year-shark-and-the-unicorns-tooth/