Which of the following is the correct sequence of blood flow in reptiles and mammals?

a) left ventricle --> aorta --> lungs --> systemic circulation
b) right ventricle --> pulmonary vein --> pulmocutaneous circulation
c) pulmonary vein --> left atrium --> left ventricle --> pulmonary circuit
d) vena cava --> right atrium --> right ventricle --> pulmonary circuit
e) right atrium --> pulmonary artery --> left atrium --> ventricle

D) vena cava --> right atrium --> right ventricle --> pulmonary circuit  

Explanation:

The pulmonary circulation is part of circulatory system which carries deoxygenated blood from the right ventricle of the heart, to the lungs, and then returns oxygenated blood from the lungs to the left atrium of the heart.

Vena cava brings deoxygenated blood to the right side of the heart-right atrium. From the right atrium, the blood is pumped through the tricuspid valve into right ventricle. Deoxygenated blood then leaves the heart from the right ventricle through the pulmonary artery. The pulmonary artery carries deoxygenated blood to the lungs, where carbon dioxide is released and oxygen is picked up during respiration (blood becomes oxygenated). The oxygenated blood leaves the lungs through pulmonary veins to the left atrium of the heart.

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the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.