Read this excerpt from "Edward Jenner and the History of Smallpox and Vaccination
The disease greatly affected the development of Western civilization.
Which evidence from the passage best supports this claim about smallpox?
Smallpox was introduced to Europe sometime between the fifth and seventh centuries.
The first stages of the decline of the Roman Empire (AD 108) coincided with a large-scale epidemic.
The Arab expansion, the Crusades, and the discovery of the West Indies all contributed to the spread of the disease.
Unknown in the New World, smallpox was introduced by the Spanish and Portuguese conquistadors.