Question

why the heart of mammals have four chambered

Answer 1

Birds and mammals are warm-blooded animals and maintain a constant body temperature by cooling themselves when they are in a hotter environment and by warming their bodies when they are in a cooler environment. Hence, these animals require more oxygen for more cellular respiration so that they can produce more energy to maintain their body temperature. Thus, it is necessary for them to have a four-chambered heart so as to separate oxygenated and de-oxygenated blood, so that their circulatory system is more efficient and can maintain their constant temperature.

Answer 2

Heart of mammals are four chambered because they need more energy, as most of the mammals are terrestrial so they require more energy.While the give birth to new ones. So they require certain more energy to make their offspring more healthy.