The Cambrian explosion was a period at the Pre-Cambrian boundary of the geologic time scale at 542 Ma. At this boundary, the fossil record shows that animals suddenly appeared in a dramatic radiation of life. A radiation is the relatively rapid development of new types of organisms that derive from a common ancestor. The Cambrian explosion is important because it marks the origination of all major animal groups called phyla.
Answer:
CORRECTION C.) EXCRETION
////B.) Digestion is the correct answer
i think its either d or b! go with d first tho <3
