I believe the answer is a. thick layer of blubber
Mammal is an warm-blooded animal that need to keep their body warm. Organ that could insulate the heat would be beneficial to keep the temperature, like layer of fat or thick fur. The example of marine mammals would be dolphin, whale, sea lion and polar bear. Thick fur will not give much benefit for mammals in water, so only polar bear have thick fur. But all of them has thick layer of blubber, so option A will be the most appropriate.
They would take in less carbon dioxide and produce less oxygen
3x +12. Look at the picture below for the explanation!
Hope this helps!
C is the answer. Your welcome
Answer:
Haemoglobin (Hb) is a protein present in red blood cells that transports oxygen and gives blood its dark/vivid red color. The amount of haemoglobin in the blood varies from person to person. Men's levels are often greater than women's. This is scientifically proven however, it is often but not all the time.