Major rivers were the main location for many cities, because of the commodities it brought. Rivers supplied the nations with water and food, for example fishes. Additionally, rivers also helped with the irrigation system for crops, with the cattle, and also worked as a way of transportation to other cities with canoes. The bigger the river the more it nourishes and helps the cities to grow. Not also what was mentioned before, but rivers were more reliable than rain. For example if a city was establishes in a middle of the desert, the citizens had to rely on the rain, that could come every day or could come once every month, to supply water for the whole civilization, but with cities near the river, especially mayor rivers, had access to water constantly.
Locations along rivers meant faster travel upstream and downstream to rule territories. The city became the place where the ruler or rulers lived together in a stationary spot. The city's location along early rivers encouraged stronger government, which in turn encouraged stronger cities.
Pea plant flowers of two colors were used i.e., Purple and White. He observed the same ratio in both cases (3:1), in the self and cross pollination. This happens because of the assumptions in Law of Segregation and Law of Independent assortment. He concluded that the purple color is the Dominant and white in recessive as in both self and cross pollination procedures.
