Which of the following is a sentence fragment? a.) realizing you are getting older is sobering. b.) hiding in the tree fort he had built as a kid. c.) knowing she would be late, she took a nap. d.) checking his mail each day was always fun.

answer: b (host)

viruses use the cells of living organisms to reproduce. the cell which is used by virus is called as "host cell". it is a living cell in which virus multiplies, example bacteria, plant or an animal cell.

in this, the virus is a parasite, which uses host cell for its benefit (reproduction) by using the cell machinary of host cell.

it is c because i got it right on my test