Answer:
Cetacean
Explanation:
Let us start with the family Delphinade which is the largest in the Cetacean order, and relatively recent: dolphins evolved about ten million years ago, during the Miocene. Dolphins are among the most intelligent animals and their often-friendly appearance and seemingly playful attitude have made them popular in past and current human culture.
A. The birds had beaks that were adapted for feeding differently
Organs , fins is the correct answer
Expiration is when food goes bad and idk how to help sorry
C.
Biotic mean alive, so we can cut off the first 2 easily. Aquatic birds eat frogs, so that one is safe for now. A decrease in something parasitic usually helps the population, so D is out too. The only one left is C.