Beginning of Essay
Every species on earth has it\\'s variants. For example, the differences between Wood Ducks and Mallards have evolved for specific reasons - namely, those which best ensure the survival of the Duck species in different environments. The same applies to humans. The ....

Middle of Essay
.... further strains and breeds under those have evolved for a very specific reason - the preservation of the species, and ultimately, life itself. Each species is like a tree, with hundreds of branches, each leading to thousands of other branches. Each branch of the tree is slightly different from the one beside it, due to living in a different environment it has had to adapt and the resulting differences are due to the combination - the formula - of genes, which has survived the best in whatever environment it has encountered. Because of this branching of the species, whenever a particular disease, a natural phenomenon, or a new predator has arrived on ....