Glycogen is an energy-storage molecule in humans. a hormone that is called insulin controls the storage of glycogen in the liver. insulin is made up of amino acids. which statement correctly identifies the types of macromolecules that are described?
a.) glycogen is a protein, and insulin is a lipid.
b.) glycogen is a lipid, and insulin is a protein.
c.) glycogen is a carbohydrate, and insulin is a lipid.
d.) glycogen is a carbohydrate, and insulin is a protein.

(D). Glycogen is a carbohydrate, and insulin is a protein.

Explanation:

Glycogen is a carbohydrate molecule, made by polymerization of glucose molecules. It represents a storage form of glucose in animals as when glucose level increases in the blood, insulin hormone activates conversion of glucose to glycogen to reduce blood sugar level.

On the other hand, insulin is a protein molecule, made up of amino acids as amino acids form proteins by polymerization. It is composed of two polypeptide chains, alpha chain (made up of 21 amino acids) and beta chain (made up of 30 amino acids).

Thus, the correct answer is option (D).

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.