Explanation:
c is an acid I think but it may not be right
It shows evolution and growth from the past and present
<span>I believe the answer is: clownfish/anemone
Clownfish is very territorial in nature. So, when they hide within the anemone, the clownfish would prevent smaller fishes from eating the anemone. In return, the anemone would prevent the bigger fish from reaching the clownfish when they hide in it.</span>