Correct Answer: B

Rationale: The correct answer is B: Re-exposure to a specific antigen. Memory cells are formed after initial exposure to an antigen. Upon re-exposure to the same antigen, memory cells quickly recognize and respond, converting into plasma cells to produce antibodies. This process is known as secondary immune response. Incorrect choices: A: An organ transplant - Organ transplant does not involve the conversion of memory cells to plasma cells. C: Release of lymphokines - Lymphokines are signaling molecules secreted by immune cells but do not directly cause memory cells to convert to plasma cells. D: Initial exposure to an antigen - Initial exposure to an antigen leads to the formation of memory cells, not their conversion to plasma cells upon re-exposure.

Correct Answer: B

Rationale: The correct answer is B: Aldosterone. Aldosterone is a hormone produced by the adrenal glands that helps regulate sodium and water balance in the body. It acts on the kidneys to increase reabsorption of sodium, leading to water retention and increased blood volume. This helps maintain blood pressure and electrolyte balance. A: Antidiuretic hormone (ADH) mainly acts on the kidneys to increase water reabsorption, not sodium retention. C: Thyroid hormone does not directly influence sodium retention. D: Insulin regulates blood sugar levels by promoting glucose uptake, it does not have a direct role in sodium retention.

Correct Answer: C

Rationale: The correct answer is C, which is to replace the foreskin over the head of the penis after washing. This is important to prevent any irritation or injury to the sensitive foreskin and glans. Leaving the foreskin retracted (A) can lead to discomfort and potential injury. Not retracting the foreskin (B) may not allow for proper cleaning. Using alcohol and a cotton swab (D) can be too harsh and irritating to the delicate tissues. Therefore, option C is the most appropriate and gentle approach to maintain proper hygiene and prevent any complications.

Correct Answer: D

Rationale: The correct answer is D: Diarrhea. Antibiotics can disrupt the normal balance of gut bacteria, leading to diarrhea. This occurs due to the overgrowth of harmful bacteria in the intestines. Monitoring for diarrhea is crucial to prevent dehydration and further complications. Platelet dysfunction (A), stomatitis (B), and oliguria/dysuria (C) are not typically associated with the disruption of normal flora by antibiotics. These symptoms are more likely related to other conditions or side effects of medications, making them incorrect choices in this scenario.

Correct Answer: B

Rationale: The correct answer is B because monitoring the site and progress of the infusion every hour is crucial to prevent complications like infiltration or infection in clients with hypertension. Choice A is incorrect as checking BP every hour is excessive. Choice C is incorrect as daily monitoring may not detect issues promptly. Choice D is incorrect as pulse rate monitoring is not directly related to IV fluid administration in this context. Monitoring the site and progress hourly ensures timely intervention if any issues arise.