The answer is d. flour and water because a mixture of flour and water is not going to be even throughout, it will be lumpy and not completely mixed.
Answer and Explanation:
It's a constrictive growth pyramid I think. They could die out in the future..
I can't remember the factors that have led to the growth
Space actually, as far as we know gravity is just a manifestation of the warping of three dimensional space created by matter. Without space, all else is doomed.
