Which of the following hormones would cause skin color to become darker?

Correct Answer: D

Rationale: The correct answer is D, Melanocyte-stimulating. Melanocyte-stimulating hormone (MSH) stimulates melanocytes in the skin to produce more melanin, leading to darker skin pigmentation. Choices A, B, and C are incorrect as Follicle-stimulating hormone (FSH) stimulates follicle growth in the reproductive system, Growth-stimulating hormone is a vague term not specific to any known hormone, and Thyroid-stimulating hormone (TSH) stimulates the thyroid gland to produce thyroid hormones, not affecting skin color pigmentation.

Correct Answer: B

Rationale: The correct answer is B. Endocrine glands release hormones directly into the blood, which is why they require a rich blood supply to ensure effective hormone distribution throughout the body. The extensive network of blood vessels allows hormones to be quickly transported to target tissues and organs, regulating various physiological functions. Choices A, C, and D are incorrect because endocrine glands do not filter waste from the blood or the glands themselves. They release hormones into the bloodstream to regulate bodily functions, making a direct connection to the blood supply crucial for their function.

Correct Answer: D

Rationale: Killer T cells recognize infected cells by detecting viral proteins displayed on the surface of these cells. The T cells possess receptors specifically designed to identify these viral proteins, allowing them to target and eliminate the infected cells. Choice A is incorrect because B cells are not directly involved in the recognition process of infected cells by killer T cells. Choice B is incorrect because tiny bits of the virus's RNA being left around the cell is not how killer T cells primarily recognize infected cells. Choice C is incorrect because while macrophages play a role in immune responses, they do not directly assist in the recognition of infected cells by killer T cells.

Correct Answer: A

Rationale: The correct answer is A: Artificial/active. The MMR vaccine provides artificial/active immunity. It works by introducing a weakened or killed form of the virus to trigger the body's immune response, leading to the production of antibodies that offer long-lasting protection against measles, mumps, and rubella. Artificial immunity is obtained through medical intervention, such as vaccination, while active immunity involves the immune system's direct response to an antigen. Choices B, C, and D are incorrect because the MMR vaccine does not provide passive immunity nor is it acquired naturally; instead, it stimulates the body to actively produce its immune response.

Correct Answer: B

Rationale: Smallpox was eradicated globally through an intensive vaccination program. The World Health Organization (WHO) led a successful global campaign to vaccinate people against smallpox, ultimately leading to its eradication in 1980. AIDS, diabetes type 1, and rheumatoid arthritis are serious conditions, but they were not eliminated through vaccination programs like smallpox. Therefore, the correct answer is B, Smallpox. AIDS is caused by the human immunodeficiency virus (HIV) and remains a significant global health issue. Diabetes type 1 is an autoimmune condition where the body attacks insulin-producing cells, leading to high blood sugar levels. Rheumatoid arthritis is an autoimmune condition that primarily affects the joints, causing inflammation and pain.