Protein, the building blocks of proteins are amino acids, different sequences and combinations of these amino acids result in huge numbers of proteins which have a variety of functions.
Homeostasis:
<em>The tendency towards a relatively stable equilibrium between interdependent elements, especially as maintained by physiological processes</em>
<span>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>
