A. flood damage is extremely costly due to homes and businesses being built on the flood plain
Explanation:
Floodplain is a waterfront region that is flooded during floods. These areas are very suitable for agriculture due to soil fertility. Such areas develop over the gutter of a valley filled with alluvial soil, over which meanders meander due to the low slope of the river course, which, in flood times, spills over its original bank and floods the adjacent region.
Flooding in this region is natural, but because of the increase in population and the need for expansion of cities, many houses and industries needed to be built in the plains of inunction. In this case, the floods cause a major problem because they cause damage to homes and industries. These losses cause often incalculable economic and emotional damage.
for the first one it is change in rainfall. the second one is 25%. the third is surpluses of food abundant food suplies. the fourth one is exploiting and misusing a resource making new products out of raw materials. hope this helps! (: brainiest?