Question

question 5
blood returning to the mammalian heart in a pulmonary vein drains first into the _.
a left atrium
b right atrium
c left ventricle
d right ventricle

Explanation:

In the mammalian circulatory system, the pulmonary veins carry oxygenated blood from the lungs. The heart has four chambers: two atria (left and right) and two ventricles (left and right). The left atrium receives oxygenated blood from the pulmonary veins. The right atrium receives de - oxygenated blood from the body via the vena cava. The ventricles (left and right) pump blood out of the heart (the left ventricle pumps to the body and the right ventricle pumps to the lungs).

Answer:

A. left atrium