a friend of mine started smoking,tries to force me to start smoking too,what discussion or argument would i have with this friend related with aerobic and anaerobic respiration?

Wow, I can't believe no one else has answered this! Just say that you don't want to , it's a terrible thing, as you know. Just tell them that you think they're throwing part of their life away. If they just get mad at you, they're not the kind of person you'd want to be friends with anyway.