Question

select the correct answer. the chart gives the number of cases of polio between 1937 and 2011. polio is an infectious disease that causes paralysis and sometimes death. the polio vaccine was introduced in 1955. what can be concluded about the polio vaccine? polio cases 1937 - 2011 cases of polio year a. it was successful in eradicating polio from the united states. b. it had no effect on the number of polio cases in the united states. c. it reduced the number of polio cases, but deaths from polio stayed constant. d. it initially lowered the number of polio cases, but the number of us cases remains high.

Explanation:

The graph shows a sharp decline in the number of polio cases after the vaccine was introduced in 1955, indicating its effectiveness in reducing cases. There is no information about deaths or the situation in the US specifically regarding eradication.

Answer:

A. It was successful in eradicating polio from the United States (this is an over - statement as the graph doesn't show eradication but a significant decline); B. It had no effect on the number of polio cases in the United States (false as the graph shows a decline); C. It reduced the number of polio cases, but deaths from polio stayed constant (no information about deaths in the graph); D. It actually increased the number of polio cases, but the number of US cases remained high (false as the graph shows a decline). The most reasonable conclusion based on the graph is that the vaccine reduced the number of polio cases, but none of the options are completely accurate based on the given information. If we have to choose the best one, we can assume the general trend of decline implies some level of success, so the closest would be A although eradication is a strong claim not fully supported by the graph.