Its not C. i took he test and got A.
Smoking ruins your lungs making it harder to breath and get oxygen
you need oxygen when you exercise so you don't faint
smokers get less so it is harder for them, its like trying to exercise while breathing through a sponge or a straw os
Answer:
A. It is a source of genetic variation
They would die because they need amylase to disgust food
<span />
The more advance the community the more complex the speciess
