The beginning of the Cambrian Period is marked by the evolution of hard body parts such as calcium carbonate shells. ... These body parts fossilize more easily than soft tissues, and thus the fossil record becomes much more complete after their appearance.
If it’s referring to sea floor spreading then the answer is D, I hate analogies but I think it’s talking about the mantle convection that slowly breaks away at the lithosphere
Answer:
a neurotransmitter binds to its receptor on a receiving cell
Explanation:
D.Releases insulin my good man
