The atria of the heart merely need to allow blood to flow into the ventricle, and therefore aren't very muscular.
The ventricles of the heart need to actually pump blood to the rest of the body, whether to the lungs or the the rest of the body.
Answer:
A carnivore consumer that eats a herbivore consumer
Color blindness I’m guessing cause I don’t see how it has anything to do with sex linked disorders
