AP BIOLOGY

Detailed explanation-1: -A typical heart has two upper and two lower chambers. The upper chambers, the right and left atria, receive incoming blood. The lower chambers, the more muscular right and left ventricles, pump blood out of the heart.

Detailed explanation-2: -The human heart consists of four chambers – two atria and two ventricles – that expand and contract in order to drive blood containing oxygen and nutrients throughout the body.

Detailed explanation-3: -In the four-chambered heart, the left half is completely separated from right half by septa. This prevents oxygenated and deoxygenated blood from mixing. This allows a highly efficient supply of oxygenated blood to all parts of the body. This is useful in animals that have high energy needs, such as birds and mammals.