Why do doctors suggest that people get a flu vaccine each year?
A B C D
Viruses replicate more rapidly over time. Viruses can mutate from year to year. Vaccines are absorbed by the body after a year. Vaccines get stronger over time.
Question: Why do doctors suggest that people get a flu vaccine each year?
(A) Viruses replicate more rapidly over time.
(B) Viruses can mutate from year to year.
(C) Vaccines are absorbed by the body after a year.
(D) Vaccines get stronger over time.

Answer: (B) Viruses can mutate from year to year.
Answer: (D) Vaccines get stronger over time.
Question: Why do doctors suggest that people get a flu vaccine each year?
(A) Viruses replicate more rapidly over time.
(B) Viruses can mutate from year to year.
(C) Vaccines are absorbed by the body after a year.
(D) Vaccines get stronger over time.
Answer: (B) Viruses can mutate from year to year.