Correct Answer: B

Rationale: The correct answer is B, Nucleus. The nucleus is the organelle in the cell that contains the genetic material (DNA). DNA within the nucleus determines the cell's functions and characteristics, making it essential for cell function and replication. Choice A, Ribosome, is responsible for protein synthesis, not genetic material storage. Choice C, Mitochondria, produces energy but does not contain the genetic material. Choice D, Endoplasmic reticulum, is involved in protein synthesis and lipid metabolism but does not house the genetic material.

Correct Answer: D

Rationale: The larynx is a vital organ of the respiratory system, responsible for producing sound and connecting the pharynx to the trachea. It plays a crucial role in breathing, swallowing, and vocalization. The brain, pancreas, and urethra are not part of the respiratory system; the brain is part of the nervous system, the pancreas is part of the digestive system, and the urethra is part of the urinary system. Therefore, the correct answer is the larynx.

Correct Answer: B

Rationale: The correct answer is B: 'To absorb nutrients.' The small intestine is the primary site for nutrient absorption in the digestive system. It plays a crucial role in absorbing nutrients from digested food into the bloodstream, facilitating the delivery of essential nutrients to the body for various functions and processes. Choices A, C, and D are incorrect because while the small intestine does contribute to the breakdown of food and does secrete digestive enzymes, its primary function is to absorb nutrients, not to store glucose.

Correct Answer: A

Rationale: The cochlea, located in the inner ear, is responsible for detecting sound waves and converting them into neural signals that are sent to the brain for processing. It plays a crucial role in the process of hearing by translating mechanical vibrations into electrical signals that the brain can interpret as sound. The semicircular canals (Choice B) are responsible for balance and detecting head movements, not hearing. The ossicles (Choice C) are three tiny bones in the middle ear that transmit sound vibrations from the eardrum to the cochlea. The Eustachian tube (Choice D) helps equalize pressure between the middle ear and the atmosphere, but it is not directly involved in the process of hearing.

Correct Answer: B

Rationale: Vitamin A is the correct answer. It is essential for maintaining healthy skin and vision, especially in low-light conditions. Vitamin A helps in the production of retinal pigments necessary for vision in dim light and supports skin health by promoting cell turnover and repair. Choice A, Vitamin C, is important for the immune system and collagen production but is not specifically known for maintaining skin and vision health. Choice C, Vitamin D, is crucial for bone health and immune function but is not directly related to skin and vision health. Choice D, Vitamin K, is necessary for blood clotting and bone health but does not play a significant role in maintaining healthy skin and vision.