Correct Answer: B

Rationale: The correct answer is B, 'Fat.' Fat provides 9 kcalories per gram, which is more than carbohydrates and proteins that provide 4 kcalories per gram each. Therefore, consuming 30 g of fat would yield a higher number of kcalories compared to the same amount of carbohydrates or proteins. Micronutrients do not significantly contribute to kcalories, making them an incorrect choice in this scenario.

Correct Answer: A

Rationale: The correct answer is A: vitamin B12. Intrinsic factor is a glycoprotein produced by the stomach that is necessary for the absorption of vitamin B12 in the small intestine. Vitamin B12 binds to intrinsic factor in the stomach, forming a complex that is then absorbed in the ileum. This absorption process is crucial for preventing vitamin B12 deficiency. Choices B, C, and D are incorrect because they do not require intrinsic factor for absorption. Folate is absorbed in the small intestine through a different mechanism, niacin can be absorbed in the small intestine without the need for intrinsic factor, and vitamin B6 does not rely on intrinsic factor for absorption.

Correct Answer: B

Rationale: The correct answer is B, galactose. Galactose naturally occurs in foods only when it is combined with glucose to form lactose, a disaccharide found in milk. Fructose is a monosaccharide found in fruits and honey. Sucrose is a disaccharide composed of glucose and fructose, commonly known as table sugar. Maltose is a disaccharide formed by the combination of two glucose molecules.

Correct Answer: B

Rationale: Lignin is the correct answer because it is a type of fiber that is not a carbohydrate and provides structure to plant cell walls. Gums (choice A), pectin (choice C), and cellulose (choice D) are all types of dietary fiber that are carbohydrates. Gums are a type of soluble fiber, pectin is found in fruits and is a soluble fiber, and cellulose is a type of insoluble fiber found in plant cell walls.

Correct Answer: A

Rationale: Carbohydrates are composed of carbon, hydrogen, and oxygen. These three elements combine to form the basic structure of carbohydrates. Oxygen is an essential element in carbohydrates, contributing to their chemical composition. Choice B (nitrogen) is incorrect as nitrogen is not a typical component of carbohydrates. Choice C (water) is incorrect as water is not an element but a compound composed of hydrogen and oxygen. Choice D (glucose) is incorrect as glucose is a specific type of sugar, not an element found in the composition of carbohydrates.