1. What is the primary function of dietary carbohydrates? A. To provide structural support to cell walls B. To serve as a buffer in the regulation of acid-base balance C. To supply energy to the body D. To enhance absorption of fat-soluble vitamins Answer: C. To supply energy to the body Rationale: Carbohydrates are the body's main source of energy, especially for the brain and muscles during exercise. 2. Which vitamin is most important for the synthesis of visual pigments in the retina? A. Vitamin A B. Vitamin C D. Vitamin E C. Vitamin K Answer: A. Vitamin A Rationale: Vitamin A is crucial for the maintenance of normal vision. It is a component of the visual pigments in the retina, which are necessary for light absorption. 3. What is the role of omega-3 fatty acids in health? A. They increase the risk of cardiovascular disease. B. They are essential components of cell membranes. C. They contribute to the development of type 2 diabetes. D. They are precursors to pro-inflammatory eicosanoids. Answer: B. They are essential components of cell membranes. Rationale: Omega-3 fatty acids are important for maintaining the fluidity and function of cell membranes, and they have anti-inflammatory properties that can reduce the risk of chronic diseases. 4. Which mineral is primarily responsible for muscle contraction and nerve transmission? A. Iron B. Calcium C. Potassium D. Magnesium Answer: B. Calcium