The answers C i'm pretty sure
Well, you have to think about how this could have happened. A lot of cities and countries have all been hit by some sort of disease or natural disaster but do they both have them. I would say false, you have to understand that not only do they go under that they also suffer from economy losses and from political misunderstandings and troubles. So no, those would not be the only two common factors.
Earth's atmosphere is 78% nitrogen, 21% oxygen, the rest 1 percent with very small percentages of other elements like Co2.
