Why do you think it is important to protect against DNA damage sperm?

Sperm DNA damage has been associated with high levels of reactive oxygen species.

High levels of which have been detected in the semen of 25% of infertile men.

the answer to your question is b

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.