Question

Short-spined sea urchin fossilswere 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?

Answer 1

As the animals die, they get covered in layers. The lowest being the oldest. The difference is showing us a direct link between the two fossils. This means that the longer-spined sea urchins existed before the shorter-spined sea urchins. And evolved to have shorter spines rather than long ones.

Step-by-step explanation:

Answer 2

It suggests that the longer spined sea urchins existed before the shorter spined sea urchins.