21. The compound C3H5(C17H3502)3 is a carbohydrate with 40 hydrogen atoms
is a lipid with 40 hydrogen atoms
is a carbohydrate with 110 hydrogen atoms
is a lipid with 110 hydrogen atoms

I kinda need points but I'll help u it might be the second one though

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.

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.