I would say that the answer is b because it can be A-blood B-blood or AB blood but since that isn't an option i would say b is the answer.
"A. Mutations" is a factor in how a species can change over time. Natural selection selects these random mutations for survival based on how fit they make their host to the environment.
The factors that most directly affect blood flow are blood pressure, blood volume, resistance and activity level.
true
