Internal. The ultimate sources of variation, the source of new heritable characteristics in populations and species, are due to mutation and recombination in chromosomes, genes, DNA.
Zone AE is the flood insurance rate zone that corresponds with flood depths greater than 3 feet. Mandatory flood insurance purchase requirements apply. Zone AH is the flood insurance rate zone that corresponds to areas of shallow flooding with average depths between 1 and 3 feet.
C, and X are the flood insurance rate zones that correspond to areas outside the. I-percent annual chance floodplain, areas of I-percent annual chance sheet flow flooding where average. depths are less than I foot, areas of I-percent annual chance stream flooding where the contributing drainage.