What is a function of the secretions produced by structure X?

Correct Answer: A

Rationale: The correct answer is A because the function of structure X's secretions is to increase the surface area of fats for better digestion and absorption in the small intestine. This is achieved by emulsifying fats into smaller droplets, aiding in their breakdown by lipase enzymes. Choices B, C, and D are incorrect as structure X is not involved in stomach acid secretion to decrease pH, protein digestion to peptides, or glycogen breakdown to maltose. The primary role of structure X is related to fat digestion, making choice A the most suitable option.

Correct Answer: C

Rationale: The correct answer is C: liver. Glycogen is primarily stored in the liver and muscles. The liver serves as a major storage site for glycogen, acting as a reservoir for glucose when blood sugar levels drop. The pancreas (A) mainly produces digestive enzymes and hormones like insulin and glucagon. The small intestine (B) is involved in nutrient absorption, not glycogen storage. The large intestine (D) is mainly responsible for absorbing water and electrolytes, not storing glycogen. Therefore, C is the correct answer.

Correct Answer: D

Rationale: The correct answer is D: carbohydrates. Maltose is a disaccharide composed of two glucose molecules, which are carbohydrates. During digestion, carbohydrates such as starch are broken down into maltose by enzymes like amylase. Lipids (A), proteins (B), and nucleic acids (C) do not directly contribute to the formation of maltose in the digestive process. Therefore, the source of maltose during digestion is carbohydrates, making option D the correct choice.

Correct Answer: C

Rationale: The correct answer is C: fat droplets. When the liver is unable to break down red blood cells, it affects the metabolism of hemoglobin, leading to decreased production of bile salts necessary for emulsifying fats. This results in decreased production of fat droplets. A: Maltose is a disaccharide formed from the breakdown of starch, not directly related to red blood cell breakdown. B: Peptides are formed from protein digestion, not directly affected by the breakdown of red blood cells. D: Nucleotides are building blocks of nucleic acids and not directly related to red blood cell breakdown.

Correct Answer: C

Rationale: The correct answer is C because salivary glands secrete an enzyme called amylase that catalyzes the breakdown of carbohydrates into maltose. Amylase specifically targets the bonds between glucose molecules in carbohydrates, resulting in the production of maltose. Therefore, the reaction of carbohydrates + H2O -> maltose is catalyzed by salivary gland secretions. Choice A is incorrect because the breakdown of proteins into peptides is not catalyzed by salivary gland secretions. Choice B is incorrect as peptides are broken down into amino acids, not the other way around. Choice D is incorrect as the breakdown of fats into fatty acids and glycerol is not catalyzed by salivary gland secretions.