Unlike mammals, fish a. release carbon dioxide. b. need oxygen to survive. c. can take in oxygen from the air. d. utilize gills for gas exchange.

Correct
Option D: Utilize gills for Gaseous Exchange

The main difference between the Fish and Mammals including the Marine Mammals is that gaseous exchange in fish is through the gills. Gills allow the fish to breathe underwater. Mammals do not have gills. Marine mammals can not breathe underwater and have to come to the surface to breathe. Therefore, the correct answer to this question is that Unlike Mammals, fish utiliza gills for gaseous exchange.