Correct Answer: D

Rationale: The direct effects of antibodies include neutralization, agglutination, and precipitation. Antibodies neutralize pathogens by binding to them and preventing their harmful effects. Agglutination involves the clumping together of pathogens, making it easier for phagocytes to engulf them. Precipitation refers to the process where antibodies bind to soluble antigens, forming large complexes that are easily removed from the body. Phagocytosis, on the other hand, is an indirect effect of antibodies where phagocytes engulf and destroy pathogens opsonized by antibodies, not a direct effect.

Correct Answer: B

Rationale: The correct answer is B: monitoring for muscle rigidity. Muscle rigidity is a hallmark sign of malignant hyperthermia, a life-threatening condition triggered by certain anesthetics. Monitoring for this sign is critical in the early identification of the condition. Choices A, C, and D are not the initial priority assessments for malignant hyperthermia. Measuring serum potassium levels, evaluating renal function, and checking arterial blood gases are not specific initial assessments for malignant hyperthermia and would not aid in its early identification.

Correct Answer: B

Rationale: The correct answer is B. Metronidazole (Flagyl) is the drug of choice for treating giardiasis, which is a common cause of diarrhea and abdominal distention. Sulfasalazine (Choice A) is used to treat inflammatory bowel disease. Trimethoprim-sulfamethoxazole (Choice C) is commonly used for urinary tract infections and Pneumocystis jirovecii pneumonia. Doxycycline (Choice D) is commonly used to treat various bacterial infections but is not the first-line treatment for giardiasis.

Correct Answer: A

Rationale: When a patient taking an oral contraceptive misses one pill, the correct action is to take two pills as soon as they remember and then continue the regular schedule. Option A is the correct answer because doubling up the dose helps maintain the effectiveness of the contraceptive. Option B is incorrect because taking only one pill after missing one may decrease contraceptive effectiveness. Option C is wrong as skipping the missed pill can also reduce effectiveness. Option D is inaccurate because taking two pills immediately is not necessary; the patient should take the missed pill as soon as remembered and then resume the regular dosing schedule.

Correct Answer: C

Rationale: A chest x-ray is the most appropriate diagnostic test for a client with a history of tuberculosis experiencing a recurrence of symptoms. A chest x-ray is commonly used to visualize the lungs and check for signs of active tuberculosis, such as abnormal shadows or nodules. While a sputum culture (Choice A) can confirm the presence of TB bacteria, it may not be the initial test ordered for a recurrence. Bronchoscopy (Choice B) and CT scan of the chest (Choice D) are more invasive and usually reserved for cases where the chest x-ray is inconclusive or to further assess complications, rather than as the initial diagnostic test for a recurrence of tuberculosis.