Question

1. what year were masks created from layers of gauze and cotton for protection against pneumonic plague (caused by yersinia pestis bacteria)?

a 1958
b 1961
c 1910
d 1979

Explanation:

In 1910 - 1911, during the Manchurian plague (a pneumonic plague), Dr. Wu Lien - teh created masks from layers of gauze and cotton for protection against the disease.

Answer:

C. 1910