Correct Answer: A

Rationale: Carbohydrate digestion begins in the mouth. The enzyme amylase, found in saliva, starts the process by breaking down starches into sugars. The esophagus is a passageway for food to reach the stomach and does not participate in digestion. The stomach mainly digests proteins and is not the primary site for carbohydrate breakdown. While the small intestine does play a crucial role in digesting carbohydrates, it is not where the process initiates. Therefore, the correct answer is the mouth.

Correct Answer: C

Rationale: The correct answer is 1500 mg to 3000 mg per day. This is the level of sodium restriction typically recommended for heart failure patients. It helps manage fluid retention and reduce blood pressure, which are both crucial in treating heart failure. A sodium intake of less than 500 mg per day (Choice A) might be too restrictive and is not typically recommended. Similarly, an intake of 1000 mg to 1500 mg per day (Choice B) falls short of the recommended range. Lastly, an intake of 3000 to 3500 mg per day (Choice D) exceeds the recommended upper limit, potentially exacerbating fluid retention and high blood pressure.

Correct Answer: C

Rationale: The correct answer is vitamin E. Vitamin E is the major antioxidant found in cell membranes, where it plays a crucial role in protecting them from oxidative damage. Although B12, beta-carotene, and vitamin A are important nutrients with specific functions in the body, they are not the primary antioxidants found in cell membranes. Vitamin E specifically localizes in cell membranes to neutralize free radicals and prevent lipid peroxidation, making it an essential antioxidant for cellular health.

Correct Answer: A

Rationale: The correct answer is A, Salivary amylase. Salivary amylase is an enzyme produced by the parotid gland that initiates starch digestion in the mouth. It helps break down starch into maltose, a simpler sugar. Choices B, C, and D are incorrect because sucrase, maltase, and lactase are enzymes involved in the digestion of disaccharides like sucrose, maltose, and lactose, respectively, in the small intestine, not in the saliva.

Correct Answer: C

Rationale: The primary function of protein in the diet is to build and repair tissues. Proteins are essential for the growth, maintenance, and repair of body tissues like muscles, skin, and organs. While proteins can be a source of energy, their primary role is not to supply energy, making choice A incorrect. Choice B is also incorrect as proteins do not synthesize vitamins; rather, they are essential nutrients themselves. Choice D is inaccurate because glycogen is a form of stored glucose in the body, not a function of protein.