which expression cannot be used to calculate the total amount paid for a meal (m) including a 15% tip?
a
m
n 15m

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.

i believe the answer is d : )

a simple sentence must have at least one dependent clause.