The correct answer would be D. DNA evidence showing it was more closely related to mammals than to other vertebrates <span />
The answer is glucose.
Hope this helps.
I don’t know why they make everyone type more than 20 characters but B sounds like the most reasonable answer.
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