1. People who are near smokers breathe in air a. that is clean because secondhand smoke is harmless
b. that contains only carbon dioxide and oxygen
c. that contains nicotine and carbon dioxide

C.That contains nicotine and carbon dioxide

Explanation:

Because since a cigarette has nicotine and it turns to carbon dioxide and nicotine because, if it was clean air it wouldn't have a smell to it either or carbon dioxide.

At least I think that what it is because I live with a smoker.

to increase speed you need to decrease frictiona dn drag hense why sprinters wear tight track suits to keep tight against there skin to keep away from wind and decrease the amount of drag you are carrying.a swimmer will wear the tightest swim suit they can possibly fit into (i was a size 28 swim suit at meets i wore a   size 23) why? because the tighter your clothing is the less drag and negative force you have. the heavier the clothe the slower and more wind gets caught. cotton tends to hold onto alot of sweat and water making it slower then say a track suit (no idea what they are made of but they are really comfy around your answer )

looks like you are missing options or a image.