What are the advantages and disadvantages of virus?

Answer 1

Your question is too general.

Viruses are by definition malevolent entities which multiply within living cells of other organisms, which can be basically any living thing of sufficient size and matching characteristics.

Viruses don't have advantages, the only good thing about getting a virus might be that your body can make antibodies to combat it and will remember the specific virus once it tries to attack your body again, if it is defeated the first time. But you'd be better off if it didn't exist or infect you in the first place.

Disadvantages of viruses are that they can be passed on to other organisms, are detrimental to your body, are sometimes lethal, and are generally hard to eradicate.