Correct Answer: A

Rationale: The correct answer is A: Zoster vaccine. The Zoster vaccine is recommended for the prevention of shingles in individuals aged 50 years and older. Shingles is caused by the reactivation of the varicella-zoster virus, the same virus that causes chickenpox. The vaccine helps reduce the risk of developing shingles and decreases the severity and duration of the illness if it occurs. Choices B, C, and D are incorrect: Haemophilus influenzae Type b (Hib) vaccine is used to prevent infections caused by Haemophilus influenzae type b, Human papillomavirus (HPV) vaccine is used to prevent HPV infections that can lead to cervical cancer and other cancers, and Pneumococcal polyvalent vaccine is used to protect against infections caused by the bacterium Streptococcus pneumoniae.

Correct Answer: A

Rationale: The correct answer is A. Finasteride has been shown to lower the risk of developing prostate cancer. Studies have demonstrated that finasteride can reduce the incidence of prostate cancer. However, it is still recommended to have regular screening to monitor for any potential issues. Choice B is incorrect as finasteride has shown to have a positive effect on reducing prostate cancer risk. Choice C is inaccurate because finasteride decreases, not increases, the risk of prostate cancer. Choice D is incorrect as regular screening is still necessary despite the risk reduction associated with finasteride.

Correct Answer: A

Rationale: During androgen therapy for hypogonadism, it is important to monitor liver function tests. Androgens can affect the liver, potentially leading to liver dysfunction. Monitoring liver function tests helps in early detection of any liver abnormalities. Kidney function tests (Choice B) are not typically affected by androgen therapy. Prostate-specific antigen (PSA) levels (Choice C) may be monitored for conditions like prostate cancer, but it is not directly related to androgen therapy for hypogonadism. A complete blood count (CBC) (Choice D) may not show specific changes related to androgen therapy for hypogonadism.

Correct Answer: A

Rationale: An attenuated antigen used in a vaccine is alive but less infectious, aiming to stimulate an immune response. Choice B is incorrect because an attenuated antigen is not highly infectious. Choice C is incorrect as the antigen is intentionally altered to be less infectious. Choice D is incorrect as an attenuated antigen is not infectious.

Correct Answer: B

Rationale: The correct answer is B: Size. Muscular atrophy is characterized by a reduction in the size of muscle cells. This decrease in size can be due to various factors such as disuse, aging, or disease. Choice A, Number, is incorrect because muscular atrophy does not involve a decrease in the number of muscle cells but rather their size. Choice C, Vacuoles, is incorrect as vacuoles are not directly related to the definition of muscular atrophy. Choice D, Lipofuscin, is incorrect as lipofuscin is a pigment associated with aging and has no direct connection to the decrease in muscle cell size seen in muscular atrophy.