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.
I heard from an insurance expert that the entire Pearland region is a Flood Hazard Zone A, which supposedly designates an area that is at high risk, and that flood insurance is required in the area.any of the areas around Clear Creek are prone more to flood, but the newer developments have built in detention ponds and better drainage systems to reduce risk. I think a lot of the older sections of Pearland are plagued by poor drainage.