The widespread introduction of which vaccine in the 20th century led to a dramatic decline in the incidence of measles?

Correct Answer: C

Rationale: The correct answer is C, the measles vaccine. The introduction of the measles vaccine in the 20th century led to a significant decrease in measles incidence due to its effectiveness in providing immunity against the measles virus. This vaccine created herd immunity, reducing the transmission of the virus within communities. The polio vaccine, chickenpox vaccine, and rubella vaccine, while important in their own right, did not have the same impact on measles incidence. Choice A, the polio vaccine, is incorrect as it targets a different disease. Choice B, the chickenpox vaccine, is incorrect as it does not directly affect measles. Choice D, the rubella vaccine, is incorrect as it specifically targets rubella, not measles.

Correct Answer: A

Rationale: The correct answer is A, The Polio Eradication Initiative, because it specifically targeted the elimination of polio through vaccination efforts. It was a focused and coordinated program aimed at eradicating polio globally. B: The Global Health Initiative is too broad and does not specifically address the eradication of polio through vaccination. C: The Immunization Initiative is also too broad and does not specify polio eradication as its primary goal. D: The Global Polio Vaccine Program is close, but it lacks the emphasis on eradicating polio entirely, which is the main goal of The Polio Eradication Initiative.

Correct Answer: A

Rationale: The correct answer is A: The World Health Organization (WHO). Founded in 1948, WHO is the primary international organization dedicated to public health. It coordinates global health initiatives, sets health standards, and responds to health emergencies. The other choices are incorrect because: B: The Centers for Disease Control and Prevention (CDC) is a US-based agency focusing on disease control within the country. C: The United Nations Health Program does not exist; there is the World Health Organization within the UN. D: The International Red Cross primarily focuses on humanitarian aid and disaster relief, not public health coordination.

Correct Answer: C

Rationale: The Elizabethan Poor Law guaranteed medical care for poor, blind, and 'lame' individuals, similar to Medicaid. Welfare (A) and food stamps (B) do not provide for medical care. Medicare (D) provides medical care to primarily the elderly population.

Correct Answer: C

Rationale: Collecting vital statistics and improving sanitation are examples of activities from early colonial America. Schools of nursing (A), vaccines (B), and public housing (D) developed after the colonial period.