Question

1. the cambrian explosion gets its name from the sudden appearance and rapid diversification of animal remains in the fossil record about 541 million years ago, during the cambrian period. some scientists argue that this ______ change in the fossil record might be because of a shift in many organisms to body types that were more likely to be preserved. which choice completes the text with the most logical and precise word or phrase? a. catastrophic b. elusive c. abrupt d. imminent

Explanation:

• Catastrophic means causing great damage or disaster. The text is about a sudden change in the fossil record, not a disaster - related change. So A is incorrect.
• Elusive means difficult to find, catch, or achieve. There is no indication in the text that the change is hard to detect or understand in that sense. So B is incorrect.
• Abrupt means sudden and unexpected. The text mentions “sudden appearance” which aligns with “abrupt change”.
• Imminent means about to happen. The change described already happened (about 541 million years ago), so D is incorrect.

Answer:

C. abrupt