in animals,viral infections sometimes remain localized. this means that they are limited to one area. this is the case for respiratory viruses sush as influenza. the "flu" is an infection of the respiratory passages that is spread by breathing in airborne cells infected with influenza viruses. vaccines can help reduce the number of cases of influenza. however, there are so many strains of the virus that it is impossible to provide immunity from all of them.
5. in the paragraph,why does the writing use influenza as an example of a viral infection?
a. to illustrate a viral that can be treated with drug.
b. to show that a viral remains dormant.
c. to give an example of a viral that stays localized.
d. to prove that a virus starts in the lymphnodes.