Correct Answer: C

Rationale: The correct answer is C. Wearing protective gear such as gown, mask, gloves, and goggles when entering the room is crucial to prevent infection in patients with AIDS. This intervention helps to minimize the risk of transmitting pathogens to the patient and vice versa. The protective gear acts as a barrier to prevent the spread of infectious agents. It also protects healthcare workers from exposure to potentially harmful pathogens. Prohibiting visitors who are severely immunodeficient (choice A) may be isolating for the patient and does not directly address preventing infection transmission. Prohibiting visitors with a cough (choice B) is important but does not cover all potential sources of infection. Ensuring protective barrier isolation precautions are in place (choice D) is a general statement and does not specify the practical steps needed to prevent infection transmission effectively.

Correct Answer: B

Rationale: The correct answer is B: Collect his urine for 12 hours. This instruction is given because the Schilling test involves collecting urine over a specific time period to measure the absorption of vitamin B12. A is incorrect because fasting is not necessary. C is incorrect as enema is not required. D is incorrect as emptying the bladder is not part of the test procedure.

Correct Answer: C

Rationale: The correct answer is C because morning administration of prednisone mimics the body's natural corticosteroid secretion pattern. Cortisol, a natural corticosteroid, is typically highest in the morning and decreases throughout the day. By taking prednisone in the morning, the client aligns the drug's peak concentration with the body's natural cortisol levels, optimizing its therapeutic effects. Choice A is incorrect because while taking the drug at the same time daily is important for consistency, it does not specifically address the rationale for morning administration. Choice B is incorrect as the effectiveness of prednisone is not solely dependent on its half-life but also on alignment with the body's natural rhythm. Choice D is also incorrect as prednisone can be taken with food and does not necessarily require an empty stomach for optimal absorption.

Correct Answer: D

Rationale: The correct answer is D, the bicarbonate-carbonic system. This buffer system is crucial in maintaining the body's pH balance. When CO2 combines with water in the blood, it forms carbonic acid, which dissociates into bicarbonate ions and hydrogen ions. Bicarbonate acts as a base, accepting excess hydrogen ions to prevent a decrease in pH. Hemoglobin and plasma proteins primarily function as transport molecules, not as buffer systems. Phosphate buffer system is present in intracellular fluids, not as commonly in the body. The bicarbonate-carbonic system is the most prevalent buffer system in the blood and plays a vital role in regulating blood pH.

Correct Answer: D

Rationale: The correct answer is D: Tensilon test. The Tensilon test involves administering edrophonium (Tensilon) to temporarily improve muscle weakness in myasthenia gravis patients, confirming the diagnosis. Other choices are incorrect: A (Mestinon test) is not a standard diagnostic test for myasthenia gravis, B (Pulmonary function studies) are not specific for myasthenia gravis, and C (Quinine tolerance test) is not a relevant test for this condition.