Why has natural selection favored the evolution of double circulation in birds and mammals?
A)because they are larger than reptiles and amphibians
B)because they use more energy than equivalent-size reptiles and amphibians
C)because they have more viscous blood than reptiles and amphibians
D)because they cannot obtain as much oxygen from the air as reptiles and amphibians

Question

Quizplus · Accepted Answer

Birds and mammals are endothermic animals that use more energy than equivalent-size reptiles and amphibians. This high metabolic demand requires an efficient delivery of oxygen and nutrients to the body's tissues and the removal of metabolic waste. The double circulation allows for a separation of the oxygen-rich blood and oxygen-poor blood, leading to better oxygen delivery and higher energy output.

Why Has Natural Selection Favored the Evolution of Double Circulation