Carbohydrates are composed of a combination of carbon, hydrogen, and which other element?

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.

Correct Answer: C

Rationale: Glucose is the primary sugar used by the body for energy and is converted from other sugars during metabolism. Sucrose is a disaccharide composed of glucose and fructose, not the end product of sugar metabolism. Fructose is a simple sugar found in fruits but needs to be converted to glucose for cellular energy. Maltose is a disaccharide composed of two glucose units and is not the final product of sugar metabolism in humans.

Correct Answer: C

Rationale: The correct answer is C, Fluoride. Fluoride is a mineral known for its ability to strengthen tooth enamel and prevent dental caries. While calcium (Choice A) is essential for strong bones and teeth, it is not specifically known for preventing dental caries. Phosphorus (Choice B) is crucial for bone health but is not directly associated with preventing dental caries. Zinc (Choice D) is not typically recognized for strengthening tooth enamel or preventing dental caries.

Correct Answer: C

Rationale: Fat is important in the diet because it provides satiety. Fat slows down digestion and absorption, which helps in making you feel full longer. This feeling of fullness is crucial in controlling food intake and managing weight. Choices A, B, and D are incorrect because fat's main role in providing satiety is related to slowing down digestion, not supplying a constant source of vitamins, speeding up digestion, or stimulating the release of digestive enzymes. While some types of fats can provide certain vitamins, the main purpose of fat in satiety is not vitamin supply.

Correct Answer: C

Rationale: Fat provides 9 kcal per gram, so 35 grams of fat provides 315 kcal. Therefore, the correct answer is C. Choice A (140) is incorrect because it doesn't consider the energy content of fat. Choice B (245) is incorrect as it miscalculates the kilocalories provided by 35g of fat. Choice D (360) is incorrect because it overestimates the kilocalories provided by 35g of fat.