This is fairly simple. For her heart cells to have so much carbon dioxide built up, that means her heart cells weren't recieving enough of an oxygen supply.
the answer is 21<span>% oxygen, </span>
The amount of food, water, and air might influence the population. If there is not enough of any of these, the population will decrease. This is because those factors are needed to survive.
Answer:
1. Flower size and color may give species B an advantage over species A. Hope it has fit