Which choice best states the main idea of the text?

Question

Tardigrades, tiny animals often called water bears, can survive being frozen, boiled, dried out, and even exposed to the vacuum of space. When conditions become harsh, they curl into a dormant state, halting nearly all metabolism until water returns. This resilience has allowed them to persist on Earth for over 500 million years.

Accepted Answer

B. Tardigrades survive extreme conditions by entering a dormant state.. Every sentence emphasizes how tardigrades endure extreme conditions, largely by going dormant, making B the main idea. A overstates 'oldest that ever lived' — the text only says they have persisted 500 million years, not that they are the oldest of all. C and D introduce claims the text never makes.

Answer

A. Tardigrades are the oldest animals that have ever lived on Earth. — The text says tardigrades have persisted for over 500 million years, which is not the same as being the oldest animals ever — you turned a long span into a superlative the passage never claims.

Answer

C. Tardigrades can only be found in water. — The nickname 'water bears' and the mention of water returning don't restrict where tardigrades live; the passage is about surviving drying out, freezing, and even vacuum.

Answer

D. Tardigrades reproduce more quickly than most other animals. — Reproduction is never discussed in the text — this choice brings in a fact from outside the passage rather than summarizing it.

Information and Ideas practice question

Answer: B. Tardigrades survive extreme conditions by entering a dormant state.

Why the other answers are wrong

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