Please help me get an answer before 10/28/20 12 am pst

Carbon could come from the 6 molecules of CO2, Hydrogen could come from the 6 molecules of H2O, and the Oxygen could come from either the CO2 or H2O, because both molecules contain oxygen.

Explanation:

the sphincter muscles at the end of the digestive tract is the anus.

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.