<span>Biotechnology is a set of techniques by which human beings modify living things or use them as tools. In its modern form, biotechnology uses the techniques of molecular biology to understand and manipulate the basic building blocks of living things. The earliest biotechnology, however, was the selective breeding of plants and animals to improve their food value. This was followed in time by the use of yeast to make bread, wine, and beer. These early forms of biotechnology began about ten thousand years ago and lie at the basis of human cultural evolution from small bands of hunter-gatherers to large, settled communities, cities, and nations, giving rise, in turn, to writing and other technologies. It is doubtful that, at the outset, the first biotechnological understood the effects of their actions, and so the reason for their persistence in pursuing, for example, selective breeding over the hundreds of generations necessary to show much advantage in food value, remains something of a mystery.</span>
