Respuesta :
Answer:
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.
Explanation:
Answer:
It suggests that the longer spined sea urchins existed before the shorter spined sea urchins.