Answer:
The answer is
Irrigation
Step-by-step explanation:
Climatic changes and the considerable reduction in rainfall obligated the populations and animals to concentrate in areas closer to water (rivers). The need for survival of these groups led to the creation of agriculture and consequently to the development of irrigation techniques, expanding the cultivable area. In the case of Egyptian Civilization, they had to understand how to deal with the Nile floods. During the flood season (July and October), the river deposited on its banks a fertile mud called humus, where cereals and vegetables were planted. A complex network of canals was built to divert water for irrigation, and dams to store.