HELP
The temperature of air at the equator is and less than air at the poles.

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).

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;