The Spread of Yellow Fever
Yellow fever is a dangerous disease that is primarily found in tropical climates. Sometimes, people infected with yellow fever suffer only mild flu-like symptoms. In other cases, however, yellow fever can be much more serious, causing kidney problems, liver failure, and sometimes, even death. For many years, people believed that the disease was spread from person to person, much like the cold or flu. However, this was not the case. It took the dedicated research of a doctor named Carlos Juan Finlay to show people how to prevent a disease that was killing people by the thousands.
In the 1800's, yellow fever was a serious threat to Cuba's population. Because people believed that the disease was spread from person to person, they tried to prevent the spread of the disease by quarantining people. However, this did not help.
Dr) Finlay had a different hypothesis. He noticed the worst outbreaks of yellow fever happened when mosquitoes were most active. This led him to theorize that mosquitoes spread the disease, not people. This was a revolutionary idea; no one had considered the possibility of mosquitoes being vectors of disease. In fact, the idea was so revolutionary that no one believed Finlay for over 20 years.
Eventually, Finlay's theory was proven. A team of military doctors led by Dr. Walter Reed conducted a series of experiments that proved once and for all that mosquitoes were indeed responsible for spreading yellow fever. Armed with this information, people took new measures to protect themselves from yellow fever. As a result of this discovery, yellow fever has almost completely disappeared from Cuba and many other nations.
What is the best summary of this passage?

Question

Quizplus · Accepted Answer

This option contains the highlights found throughout the text, beginning with the reactions to yellow fever as a disease, the fact that researchers discovered useful information about it, and the fact that it has been made less of a threat. Therefore, this is the most accurate summary of the passage.
The causes of yellow fever were hard to understand in the early stages of the outbreak of the disease. 
Incorrect. The primary purpose of the passage is not to warn, but rather, to inform the reader of Dr. Finlay's discovery and research. The dangers associated with yellow fever are mentioned as supporting details in paragraph 1.
Thanks to doctors and researchers, yellow fever is no longer a threat.
Incorrect. Nothing in the text persuades the reader not to visit certain areas or to be more cautious. The text is informative in nature because it explains the research and contributions of Dr. Finlay.
Dr. Finlay was a revolutionary researcher who contributed greatly to the world of medicine. 
Incorrect. Although this is true, it is an ending detail provided in paragraph 4. More of the passage is spent discussing Dr. Finlay's research and contributions, and Dr. Walter Reed based his research off of Dr. Finlay.