If there was no gravity the rocks will have no where to drop off because gravity is what holds down everything, so there would be no build up of land.
Answer:
B. The ethnicity and language of the people in the area. This is one of many reasons for the boundaries that were setup in India.
Explanation:
I would say that one reason is since developed countries are so advanced in every aspect...they have no time to reproduce, so there are no replacements for old people, hence the increase in the average population age.
There are many people in urban areas. If there are floods, it could kill a lot of people. Also, floods sometimes damage buildings. If the buildings collapse, it would cause a big problem.