Which vitamin is essential for bone health?

Correct Answer: B

Rationale: Vitamin D is the correct answer. It is essential for bone health as it helps in the absorption of calcium, a crucial mineral for maintaining strong and healthy bones. Adequate levels of Vitamin D are necessary to prevent conditions like osteoporosis and ensure optimal bone development and strength. Choice A, Vitamin A, is important for vision and immune function, but it is not directly related to bone health. Choice C, Vitamin C, is essential for collagen synthesis and immune function, but it is not primarily responsible for bone health. Choice D, Vitamin K, plays a role in blood clotting and bone metabolism, but Vitamin D has a more direct impact on bone health through its role in calcium absorption.

Correct Answer: B

Rationale: The correct answer is B: To store and concentrate bile. The gallbladder's primary function is to store and concentrate bile, which is produced by the liver. Bile is released into the small intestine to aid in the digestion and absorption of fats. It helps in emulsifying fats and facilitating their breakdown by enzymes for better absorption. Choices A, C, and D are incorrect because the gallbladder does not produce bile (it is produced by the liver), detoxify harmful substances, or directly break down fats. Its main role is to store and concentrate bile before releasing it into the small intestine.

Correct Answer: C

Rationale: The correct answer is C: 'To carry oxygen.' Hemoglobin in red blood cells binds to oxygen in the lungs and transports it to the tissues and organs throughout the body. This oxygen transport is crucial for cellular respiration and the overall functioning of the body. Choices A, B, and D are incorrect because hemoglobin's primary function is not to transport nutrients, fight infections, or produce energy in red blood cells.

Correct Answer: C

Rationale: Platelets, also known as thrombocytes, play a crucial role in blood clotting. When there is an injury, platelets adhere to the site and release substances that form a clot, preventing excessive bleeding. This function is vital for maintaining hemostasis and preventing blood loss. Choice A is incorrect because red blood cells, not platelets, are responsible for transporting oxygen. Choice B is incorrect as white blood cells are primarily responsible for fighting infections. Choice D is incorrect as nutrients are mainly transported by plasma and red blood cells, not platelets.

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.