Jenner prepared the vaccine for small-pox virus by using
A. attenuated small pox virus
B. small doses of small pox virus
C. attenuated cow pox virus
D. large dose of small pox virus
Answer:C
Jenner prepared the vaccine for small-pox virus by using
A. attenuated small pox virus B. small doses of small pox virus C. attenuated cow pox virus D. large dose of small pox virus