Ques : Edward Jenner developed smallpox vaccine by observing that a person who previously has caught which of these infections did not catch smallpox?

Cowpox

Ques : Edward Jenner developed smallpox vaccine by observing that a person who previously has caught which of these infections did not catch smallpox?

A. Chickenpox

B. Monkeypox

C. Sheeppox

D. Cowpox

Ans :  D. Cowpox