Question

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.

Answer 1

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

Answer 2

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

Step-by-step explanation: