The specialization of work is as old as the first human groupings, and it was through division by sex. The invention of the wheel dates from at least 2000 years before Christ, and can be extended up to 3,500 years if we take into account the first illustrations of a wheel. The controlled use of fire, in turn, dates back more than a million years, while the development of agriculture is about 10,000 years old. Thus, among the discoveries and inventions pointed out. It is worth noting, however, that the invention of the wheel, while important, would not contribute to such a large population growth.
Agriculture (letter d), gradually improved from 5,000 BC, is the fundamental factor for population growth, which could now settle, rather than live as a nomad.
Migration may lead to an improvement in income distribution because labor exodus may generate tight labor market conditions in supplying areas, resulting in increased wages of rural workers. The evidence of Pakistan tended to support this.
Answer: Because more and more agriculture is one of the main "professions", where the use of water is extremely essential. Therefore, there is a great demand for it due to the scarcity that it has been having, since this is a renewable medium.
