Correct Answer: B

Rationale: The larynx is an essential organ of the respiratory system. It plays a crucial role in producing sound, protecting the trachea from food aspiration, and regulating the airflow to and from the lungs. The brain is part of the nervous system, the urethra is part of the urinary system, and the pancreas is part of the digestive system. Therefore, they are not directly related to the respiratory system's functions.

Correct Answer: B

Rationale: The cerebrum, specifically the motor cortex located within it, is responsible for controlling voluntary movements such as walking, writing, and speaking. This region of the brain plays a crucial role in coordinating and executing voluntary muscle actions, making it the correct answer in this context. The cerebellum (Choice A) primarily coordinates balance, posture, and coordination of voluntary movements but does not control voluntary movement itself. The brainstem (Choice C) is responsible for basic life functions like breathing and heart rate, not voluntary movements. The medulla oblongata (Choice D) controls vital functions like blood pressure and breathing, not voluntary movement.

Correct Answer: A

Rationale: The spleen plays a crucial role in the lymphatic system by filtering blood, specifically removing old or damaged red blood cells. Additionally, the spleen produces lymphocytes, a type of white blood cell that plays a key role in the immune response by helping to fight off infections. Therefore, the correct answer is A, as the spleen is primarily involved in blood filtration and the production of lymphocytes rather than storing vitamins or regulating body temperature.

Correct Answer: C

Rationale: The alveoli are tiny air sacs in the lungs responsible for the exchange of gases, specifically oxygen and carbon dioxide, during breathing. Oxygen is taken in and carbon dioxide is released through this process, enabling the body to receive oxygen and expel carbon dioxide. Choice A is incorrect because the alveoli do not absorb oxygen but facilitate the exchange of gases. Choice B is incorrect as the alveoli do not remove carbon dioxide but aid in the exchange of gases. Choice D is incorrect as the alveoli are not involved in regulating blood pressure but in gas exchange.

Correct Answer: A

Rationale: Vitamin A is the correct answer. It is crucial for maintaining healthy vision and skin. Vitamin A plays a vital role in supporting normal vision, skin health, and immune function. Specifically, it is important for the health of the retina and is essential for the formation of rhodopsin, a protein in the retina necessary for low-light and color vision. Vitamin C (Choice B) is important for collagen synthesis and immune function, but it is not primarily associated with vision health. Vitamin D (Choice C) is crucial for bone health and immune function, while Vitamin E (Choice D) acts as an antioxidant, protecting cells from damage, but neither are primarily linked to vision and skin health like Vitamin A.