Where does most nutrient digestion and absorption occur?

Correct Answer: B

Rationale: The small intestine is the correct answer. It is the primary site for nutrient digestion and absorption in the digestive system. The small intestine plays a crucial role in breaking down carbohydrates, proteins, and fats into forms that can be absorbed by the body. While the large intestine absorbs water and electrolytes, the majority of nutrient absorption occurs in the small intestine. The stomach primarily functions in the initial digestion of proteins, and the mouth begins the mechanical breakdown of food through chewing.

Correct Answer: B

Rationale: The correct answer is B. Viscous (soluble) fiber binds with bile acids in the intestine, which are then excreted. The liver must use cholesterol to make more bile acids, thereby lowering blood cholesterol levels. Choice A is incorrect as insoluble fiber does not bind with cholesterol in the large intestine. Choice C is incorrect as soluble fiber does not directly bind with cholesterol in the blood. Choice D is incorrect as insoluble fiber does not convert to bile in the large intestine to bind with cholesterol.

Correct Answer: D

Rationale: The gallbladder releases bile into the small intestine to help digest fats. Bile emulsifies fats, breaking them down into smaller droplets for easier digestion. The stomach primarily releases gastric acid, the liver produces bile but stores it in the gallbladder, and the pancreas secretes bicarbonate to neutralize stomach acid in the small intestine. Therefore, choices A, B, and C are incorrect.

Correct Answer: A

Rationale: The correct answer is an ionic bond. An ionic bond is formed when a positively charged metal ion joins with a negatively charged nonmetal ion, resulting in a transfer of electrons. In contrast, a covalent bond involves sharing electrons between atoms rather than complete transfer. Functional groups are specific groups of atoms within molecules that determine the molecule's chemical properties. Metallic bonds occur between metal atoms where electrons are shared across a delocalized electron cloud.

Correct Answer: D

Rationale: The correct answer is D, All of the above. Carbohydrates and proteins provide 4 kcal per gram, while fats provide 9 kcal per gram. Therefore, all three energy-yielding nutrients provide different amounts of energy to the body. Choice A, B, and C are incorrect because each of them individually provides a specific amount of energy per gram, but when considering all nutrients together, they collectively cover the spectrum of energy provision to the body.