Why does a coastal area have less variation in temperature than a noncoastal area?

Coastal areas have moderate temperature because the land absorbs and radiates heat much faster than sea. So, during the day cool air from sea rush towards the land and during night cool air from the land rush towards sea

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).