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 VE is the flood insurance rate zone that corresponds to coastal areas that have additional hazards associated with storm waves. Mandatory flood insurance requirements apply. Zone X and Zone X-500 are flood insurance rate zones that are outside the flood plain or with average flood depths of less than 1 foot.
The Federal Emergency Management Agency (FEMA) has placed more than 20,000 communities in the United States into a category of flood zones. Each community is able to participate in the agency's National Flood Insurance Program (NFIP), with premium rates determined by the risks of flooding.