Question

Milkmaids who were infected with the cowpox virus, were resistant to small pox virus because ______________________.

• A. both the viruses were closely related to each other
• B. both the viruses were the same
• C. cowpox virus was more deadly than the small pox virus
• D. small pox virus was more deadly than the cowpox virus

Answer 1

The correct option is A both the viruses were closely related to each other

Since the cowpox virus is closely related to the small pox virus, getting infected with cowpox worked as vaccines for the milkmaids. When they were injected with the small pox virus, their immune systems were quickly able to respond and kill them.