Each stage of the sleep cycle lasts about how long? an hour 30 minutes 15 minutes 90 minutes

the answer is otpion c) understanding

he wants to be heard one more time. he wants to be understood. he needs the truth one more time.

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.