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

Ricky Bates

10 April, 10:54

+2

Answers (2)

Know the Answer?

Maria Ward · Answer 1

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

Fawn · Answer 2

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