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.
1 For more information on flood zones, see FEMA's FloodSmart web page. 2  Zone AE are areas that have a 1% probability of flooding every year (also known as the 100-year floodplain), and where predicted flood water elevations above mean sea level have been established. Shaded Zone X are areas that have a 0.2% probability of flooding every year (also known as the 500-year floodplain). 2  Properties in Shaded Zone X are considered to be at moderate risk of flooding under the National Flood Insurance Program.