Correct Answer: A

Rationale: The correct answer is A: Levonorgestrel (Plan B). Levonorgestrel is the most commonly prescribed medication for emergency contraception within 72 hours of unprotected intercourse. It is effective when taken within 72 hours after intercourse, with better efficacy the sooner it is taken. Choice B, Mifepristone (RU-486), is not indicated for emergency contraception but is used for medical abortion. Choice C, Ulipristal acetate (ella), is another option for emergency contraception that is effective up to 120 hours after unprotected intercourse. Choice D, Estradiol (Estrace), is not used for emergency contraception.

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: The correct answer is A. Hormone replacement therapy (HRT) is associated with an increased risk of cardiovascular events, including heart attack and stroke, especially in patients with a history of cardiovascular disease. Choice B is incorrect because HRT is not typically used to decrease the risk of osteoporosis. Choice C is incorrect as mood and energy level improvements are not the primary risks associated with HRT. Choice D is incorrect because HRT may actually increase the risk of breast cancer in some individuals.

Correct Answer: A

Rationale: The correct answer is A: Levonorgestrel (Plan B). Levonorgestrel is the most commonly prescribed medication for emergency contraception within 72 hours of unprotected intercourse. It is effective when taken within 72 hours after intercourse, with better efficacy the sooner it is taken. Choice B, Mifepristone (RU-486), is not indicated for emergency contraception but is used for medical abortion. Choice C, Ulipristal acetate (ella), is another option for emergency contraception that is effective up to 120 hours after unprotected intercourse. Choice D, Estradiol (Estrace), is not used for emergency contraception.

Correct Answer: D

Rationale: The correct answer is D, 'Increased cardiopulmonary rates.' The fight or flight response, activated by stress, is a non-specific physiological reaction that prepares the body to deal with perceived threats. In this response, the heart rate and breathing rate increase to supply more oxygen to muscles and vital organs, enabling a rapid response in dangerous situations. Choices A, B, and C are incorrect because decreased pupillary light response, increased GI motility, and decreased short-term memory are not typical manifestations of the fight or flight response.