Viruses are usually considered to be nonliving.
Viruses viruses are the smallest agents of disease.
The smallest agents of disease are usually considered to be nonliving.
What are usually considered to be nonliving?

a. direct damage to the lungs
b. bacteria
c. harmful substances
d. major threat to health
e. humans
f. the smallest agents of disease
g. starfish
h. Contaminated wounds