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).
<span>Because DNA contains the genes that instruct the cells in how to build proteins. The genetic codes are the blueprints for each protein, and proteins control all biochemical reactions in the cell (as enzymes) and also form the structure of the cell, which becomes the structure of the entire organism. Without knowing how to build proteins, higher organisms would never have evolved.</span>
Mitosis is the process in which cell division occurs.
In plant cells the vacuole stores all of the cells nutrients and food.
1the atmosphere<span> also protects living </span>things<span> on Earth from the sun's harmful ultraviolet radiation. 2</span>tmosphere filters out these dangerous rays. 3The atmosphere<span> also helps to sustain life of Earth. .4blocks harmful electromagnetic 5.provide oxgen</span>