Answer: It shows the evolution of mutations. Throughout the lifetime of animals and humans depending on their way of life and how they life it they will slowly mutate into a different animal to be able to life that way..
Explanation: Example- Whales use to have legs and walked around the earth. But also loved to swim and play in water. Over time they began to adapt and mutate into what we know f whales now. With no legs, they have large fins to help them swim in the oceans.
Basically your answer is Evolution of the Animal