Can someone give some examples of how peer pressure can also be positive?

  Peer pressure can be positive if it influences someone to do something beneficial or avoid harmful situations. An example of positive peer pressure is if one of your friends starts smoking cigarettes. Smoking is pretty bad for you. You can positively pressure you friend to stop smoking by telling them the harmful effects smoking has on the human body and you can positively pressure your friend to get help.  

Explanation:   :)

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.