Correct Answer: B

Rationale: Schwann cells are a type of neuroglia found in the peripheral nervous system. They are responsible for producing the myelin sheath around axons of neurons, which helps with the conduction of nerve impulses. Therefore, Schwann cells are typically found in the nervous system. Choices A, C, and D are incorrect because Schwann cells are specifically associated with the nervous system and are not found in the digestive, skeletal, or muscular systems.

Correct Answer: B

Rationale: The tympanic membrane, also known as the eardrum, is the most medial feature in the ear. It separates the outer ear from the middle ear and serves as a barrier that vibrates in response to sound waves, transmitting vibrations to the middle ear ossicles. The pinna, cochlea, and outer canal are located more laterally in the ear anatomy. The pinna is the visible part of the ear located on the lateral side of the head, the cochlea is a spiral-shaped structure in the inner ear responsible for hearing, and the outer canal refers to the external auditory canal leading to the eardrum.

Correct Answer: D

Rationale: The mitral valve, also known as the bicuspid valve, separates the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle to the left atrium during the heart's contraction. Therefore, option D, 'Left atrium and left ventricle,' is the correct answer. Choices A, B, and C are incorrect because they do not represent the parts separated by the mitral valve.

Correct Answer: A

Rationale: The correct answer is A. Vitamins are essential nutrients that the body needs in small amounts but do not provide energy like carbohydrates, fats, and proteins do. Carbohydrates, fats, and proteins are macronutrients that supply energy to the body when broken down during metabolism. Vitamins, on the other hand, play crucial roles in various bodily functions but are not a source of energy. They are essential for supporting growth, immune function, and overall health, but do not contribute directly to energy production. Choices B, C, and D are incorrect because carbohydrates, fats, and proteins are macronutrients that provide energy to the body when metabolized.

Correct Answer: B

Rationale: Iodine is the mineral that supports the function of the thyroid. The thyroid gland requires iodine to produce thyroid hormones, which are essential for regulating metabolism and other important bodily functions. A deficiency in iodine can lead to thyroid disorders such as hypothyroidism or goiter. Manganese (Choice A), Phosphorus (Choice C), and Zinc (Choice D) do not play a direct role in supporting the thyroid function like iodine does. While these minerals are important for various bodily functions, they are not specifically required for the thyroid gland's hormone production.