Regrowth: repairing a part is not copying a whole animal

Tests: 2 of 5 right · Exam: 2 of 3 right · Kind: ★★ · Understood: 7 of 8 · Run: 2026-11-05, commit 610eccd1d

Lesson 411 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.

Test 1 · ★★ · right ✓

A crab grows larger over several months. According to the lesson, how do arthropods increase in size?

1. By turning into a new individual each time — no support
2. By growing an extra shell over the old one — no support
3. By shedding and replacing the exoskeleton — ← Mova's choice · ✓ the right answer · score 12
4. By stretching a hard covering that never changes — no support

Why: It took the question to ask what something is like. It chose option 3 with score 12, the only option with support. Its support: lesson 411, line 8: «Arthropods increase in size by shedding and replacing their exoskeleton during growth.», reached through the same lesson line as the sentence the question matched. What matched: the same action «replace» (+4); the same doer «arthropods» (+4); the same thing acted on «exoskeleton» (+4).

Test 2 · ★★ · wrong ✗

A marked animal has one missing appendage in an earlier photograph and a replacement later. Only one individual is tracked. Which conclusion fits?

1. Two animals must now exist — ← Mova's choice · score 0
2. The animal changed its species — score 0
3. Part replacement is supported — ✓ the right answer · no support
4. The earlier animal must have died — score 0

Why: It took the question to ask who or what does it. It chose option 1 with score 0, tied with another option at 0 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 411, line 1: «In Where Animals Talk, Crab promises that all his claws will grow again after two months in shallow water. A character's promise is a story event, not a measur…», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+3); the same doer «animals» (+1). Against it: a different action (counts against) (-4). The right option, 3, found no support in what it remembers.

Test 3 · ★★ · wrong ✗

A juvenile animal regrows a structure during growth. May its timetable be applied to every adult of every species?

1. Yes, because time is the only variable — ← Mova's choice · no support
2. Yes, because the structure has a name — no support
3. Yes, because all adults are larger — no support
4. No, the relevant biological conditions may differ — ✓ the right answer · no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown.

Test 4 · ★★ · right ✓

One observation follows a repaired appendage; another follows a new individual formed from a fragment. What differs?

1. Whether living tissue is involved at all — no support
2. Whether either observation has a date — no support
3. Whether a body structure is involved — no support
4. Whether a new individual is produced — ← Mova's choice · ✓ the right answer · score 3

Why: It took the question to ask who or what does it. It chose option 4 with score 3, the only option with support. Its support: lesson 411, line 4: «Some animals can produce new individuals from body fragments, but that is a different outcome from replacing one appendage. Ask what grew, which individual it…», reached through the remembered sentence the question matched. What matched: the same action «produce» (+3).

Test 5 · ★★ · wrong ✗

A tale puts an animal in shallow water before a promised recovery. What does that sequence alone establish?

1. Shallow water is the only possible cause — no support
2. Two months is the schedule for every species — score -2
3. Every missing part must be replaced — ← Mova's choice · score 10
4. It does not establish the cause of regrowth — ✓ the right answer · score 10

Why: It took the question to ask what it is done to. It chose option 3 with score 10, tied with another option at 10 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 411, line 9: «Asexual reproduction produces a new individual; replacing a part on the same individual does not by itself establish reproduction.», reached through the same lesson line as the sentence the question matched. What matched: the same action «replace» (+5); it fills the role the question asks for (+3); the same thing acted on «part» (+2). The right option, 4, scored 10.

Exam question 1 · formal language · right ✓

Two unlabelled pictures show similar crabs, one missing a claw and one with two claws. What is needed before calling this repair of the same animal?

1. Evidence identifying the individual across time — ← Mova's choice · ✓ the right answer · score 5
2. A guess based only on claw number — no support
3. A longer title for the pictures — no support
4. An assumption that similar animals are identical — no support

Why: It took the question to ask what it is done to. It chose option 1 with score 5, the only option with support. Its support: lesson 411, line 3: «Suppose an observer follows the same identifiable crab and sees a missing claw replaced. That is evidence of a repaired part on that individual. It does not, b…», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+3); the same thing acted on «evidence» (+2).

Exam question 2 · formal language · wrong ✗

A report says one species replaced a structure in one observed case. Which summary keeps its scope?

1. Every species can replace every part — no support
2. The result guarantees the tale's timetable — no support
3. That case supports that observed replacement — ✓ the right answer · no support
4. The animal necessarily produced offspring — ← Mova's choice · score 5

Why: It took the question to ask who or what does it. It chose option 4 with score 5, the only option with support. Its support: lesson 411, line 5: «Regeneration can replace a structure without producing a new animal.», reached through the same lesson line as the sentence the question matched. What matched: the same thing acted on «new animal» (+4); the same action «produce» (+2). Against it: a different doer (counts against) (-1). The right option, 3, found no support in what it remembers.

Exam question 3 · formal language · right ✓

An observer tracks one marked animal. A lost leg is replaced, and no other animal appears. What would have to be observed to call this reproduction?

1. A new individual being produced — ← Mova's choice · ✓ the right answer · score 8
2. A date written in the observer's notebook — no support
3. A replacement leg on the same animal — no support
4. A longer leg than the one that was lost — no support

Why: It took the question to ask who or what does it. It chose option 1 with score 8, the only option with support. Its support: lesson 411, line 9: «Asexual reproduction produces a new individual; replacing a part on the same individual does not by itself establish reproduction.», reached through a sentence linked to the one the question matched. What matched: the same action «produce» (+5); the same thing acted on «new individual» (+3).

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/biology/411-regrowth-repair-and-new-individuals/

📝 Regrowth: repairing a part is not copying a whole animal