I would go with B & D because they change over time and they can go extinct like those big octopus in the oceans, they are rare to see in my opinion because they can blend in with other things that keeps them away from danger.
Answer:
Explanation:
Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population.
ORR
Struggle for existence, variation and inheritance. These are said to be the necessary and sufficient conditions for natural selection to occur.