Correct Answer: B

Rationale: In respiratory acidosis, the serum potassium level is expected to be elevated. This occurs because potassium shifts from cells into the bloodstream as a compensatory mechanism to maintain acid-base balance. Choices A, C, and D are incorrect. A normal potassium level is not expected in respiratory acidosis. A low potassium level is more commonly associated with alkalosis, not acidosis. The potassium level is indeed related to pH changes in respiratory acidosis, leading to the expected elevation.

Correct Answer: C

Rationale: The correct answer is C: Calcium. Calcium is essential for maintaining bone health and is crucial in preventing osteoporosis. Adequate calcium intake, along with vitamin D, is vital for bone strength. While other minerals and vitamins are also important for overall health, in the context of preventing osteoporosis, calcium plays a primary role. Potassium (Choice A), Magnesium (Choice B), and Vitamin B12 (Choice D) are important for various bodily functions but are not as directly linked to preventing osteoporosis as calcium.

Correct Answer: A

Rationale: Active transport is the correct answer as it accurately describes the process involved in the sodium-potassium pump. The pump utilizes energy to move ions against their concentration gradient, maintaining cellular concentrations. Diffusion (choice B) is a passive process where substances move from an area of higher concentration to lower concentration. Filtration (choice C) involves the movement of solutes based on pressure gradients. Osmosis (choice D) is the movement of water across a semipermeable membrane.

Correct Answer: A

Rationale: Metformin is classified as an antihyperglycemic agent because it works by reducing hepatic glucose output and decreasing glucose absorption from the gut, thereby preventing hyperglycemia. Choice B, a hypoglycemic agent, is incorrect as hypoglycemic agents stimulate insulin production, which is not the mechanism of action of metformin. Choice C, an insulin analogue, is incorrect as metformin is not a type of insulin but a distinct medication. Choice D, a pancreatic alpha cell stimulant, is incorrect as metformin does not stimulate any pancreatic cells, but rather acts on the liver and gut to lower blood sugar levels.

Correct Answer: C

Rationale: When folic acid is given without determining the underlying cause of anemia, the symptoms of pernicious anemia may be masked, potentially delaying the correct treatment. Folic acid alone does not protect against the central nervous system changes seen in pernicious anemia, which are related to Vitamin B12 deficiency. Folic acid and Vitamin B12 are both crucial for cell growth and division. Administering folic acid without knowing the specific type of anemia could lead to a delay in addressing the root cause. Option A is incorrect because folic acid is essential for erythropoiesis, the production of red blood cells. Option B is incorrect as excessive folic acid can cause toxicity, but it is not the primary concern in this context. Option D is incorrect because folic acid treatment for anemia does not directly impact intrinsic factor, which is related to Vitamin B12 absorption.