Change in the external Environment may resulted in the changing in the population of beetles.
The answer is D, carbon dioxide, because carbon dioxide is used in photosynthesis. The answer is not b, glucose, because the end product of photosynthesis is glucose.
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