Short-spined sea urchin fossils were found directly above long spined sea urchin fossils in a layer of rock. What do the differences between the two sets of sea urchin fossils suggest about them?

A. The longer spines developed as the shorter-spined sea urchins grew older.

B. The longer-spined sea urchins existed before the shorter-spined sea urchins.

C. The shorter-spined sea urchins stretched their spines to ward off predators.

D. The shorter spines did not protect the sea urchins well enough and they died off.

Question

20 October, 01:50

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Answers (2)

Know the Answer?

Lilia Murphy · Answer 1

B) The longer-spined sea urchins existed before the shorter-spined sea urchins.

Makayla · Answer 2

Choice B, because of evolution. The longer spines weren't needed, so they essentially died off, leaving urchins with shorter spines