Correct Answer: A

Rationale: Step-by-step rationale for why answer A is correct: 1. Having intercourse with just the spouse means a monogamous relationship with a trusted partner, minimizing risk of exposure to HIV. 2. It eliminates the risk of contracting HIV from multiple sexual partners. 3. This choice adheres to safer sex practices by reducing the chances of exposure to HIV. 4. This choice also promotes trust and communication within the relationship, further reducing the risk of HIV transmission. Summary: - Choice A is correct as it promotes monogamy and reduces the risk of exposure to HIV. - Choices B, C, and D do not guarantee zero risk of HIV transmission as blood donations, HIV antibodies, and condom use can still pose risks if not used or implemented correctly.

Correct Answer: B

Rationale: The correct answer is B: Dyspnea. Dyspnea is a common sign of organ rejection after heart transplantation, indicating possible heart failure. Low white blood cell count (A) is not typically a direct sign of organ rejection. ECG changes (C) may occur but are not specific to organ rejection. Fever (D) is a non-specific symptom and can be caused by various factors. Dyspnea is a key indicator that the transplanted heart is not functioning properly and should be closely monitored.

Correct Answer: D

Rationale: The correct answer is D because a brain abscess can be caused by direct invasion of the brain, spread of infection by other organs, and spread of infection from nearby sites. Direct invasion occurs when bacteria enter the brain tissue directly, such as through trauma or surgery. Infections from other organs, like the lungs or heart, can spread through the bloodstream to the brain. Infections from nearby sites, such as the ears or sinuses, can also spread to the brain. Therefore, all of these mechanisms can lead to the formation of a brain abscess. Choices A, B, and C individually do not cover all the possible causes of a brain abscess, making D the correct choice.

Correct Answer: C

Rationale: The correct answer is C: 0.45% saline. This solution is hypotonic because it has a lower osmolarity compared to the intracellular fluid. It contains fewer solutes than the cells, causing water to move into the cells by osmosis, potentially causing them to swell. Normal saline (A) and Ringer's lactate (B) are isotonic solutions, meaning they have a similar osmolarity to the intracellular fluid and do not cause significant water shifts. 5% dextrose in normal saline (D) is a hypertonic solution, containing more solutes than the cells, leading to water movement out of the cells.

Correct Answer: C

Rationale: The correct answer is C: Osteoporosis. Long-term corticosteroid therapy, such as prednisone, is known to cause bone loss and increase the risk of osteoporosis. Corticosteroids inhibit bone formation and increase bone resorption, leading to decreased bone density and increased fracture risk, which can manifest as severe back pain. Incorrect choices: A: Hypertension - Corticosteroids can cause fluid retention and sodium retention, leading to hypertension, but it is not typically associated with severe back pain. B: Muscle wasting - Corticosteroids can lead to muscle weakness, but severe back pain is not typically related to muscle wasting. D: Truncal obesity - Corticosteroids can cause weight gain, especially in the trunk area, but this is not directly responsible for severe back pain.