Viruses are not cells.
Viruses viruses are the smallest agents of disease.
The smallest agents of disease are not cells.
what are not cells?

(a) Something coming from a gland
(b) remains of prehistoric life
(c) smallest agents of disease
(d) an infected needle
(e) an area swollen with pus
(f) They may not survive.
(g) Leptospirosis
(h) microorganisms