The main thing would be to not smoke. But also if you are around someone who smokes, try to limit interaction with them while they are smoking. second hand smoke can be just as deadly. Also doing things like using smoke free facilities, like smoke free hotel rooms and restaurants.
The answer is the upper back muscles. Hope I helped!
Answer:
refrigeration and gmos (this is based on research but it is souly opinion based because it all depends on what you think is the most important. please accept this answer with discretion.)
Explanation:
refrigeration because it helped improve shelflife for food all across the world.
gmos because it saved many crops from complete devastation and saved farmers from endless debt and depression (of money).