The use of rivers for irrigation in agriculture began in about

The correct answer is: 6000 B.C.

The use of rivers for irrigation began in the lands of Egypt and Mesopotamia; the ancient civilizations used the water from Nile, Tigris, and Euphrates rivers when these were in a flooding state.

The flooding waters usually ocurred from July to December. The technique consisted in diverting the river water to the fields, and drained back to preserve the growing cycle.

thing is, i'm afraid, you can't.

the most you can do is log out and never log in again.

the anwser is a) to prevent military conflict