In 1954, the American scientist Jonas Salk developed a vaccine for the prevention of
A. polio.
B. tuberculosis.
C. influenza.
D. yellow fever.
E. typhoid.
Answer: A
In 1954, the American scientist Jonas Salk developed a vaccine for the prevention of
A. polio.
B. tuberculosis.
C. influenza.
D. yellow fever.
E. typhoid.