Question

which best describes how the common cold spreads in the human body?
a. bacteria burst out of normal cells, killing them.
b. viruses insert dna into bacteria.
c. viruses replicate inside respiratory cells.
d. bacteria inject dna into normal cells.

Explanation:

The common cold is caused by viruses. Viruses infect and replicate inside human respiratory cells to spread within the body. Bacteria - related processes described in A, B and D are not how the common cold spreads.

Answer:

C. Viruses replicate inside respiratory cells.