Smallpox is a virus that causes a rash that then turns into painful blisters. The last known case of smallpox was in 1977. What is the best explanation for the eradication of smallpox?

Smallpox was eradicated through vaccination: an effective vaccine helped prevent people from catching and spreading the virus. Exercising more and genetic testing do not stop the spread of smallpox, and antibacterial products target bacteria, not viruses. Therefore, the best explanation is that an effective vaccine was developed.

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