Early civilizations modified the physical environment by creating irrigation systems and dams. what was the purpose of these modifications?

a to reduce the animal population

b to create more fertile land for growing crops

c to provide better defense for cities

d to allow for easier travel between cities

(can someone . has to be turned in 1) - explain one similarity between the federal, state, and local governments. ( question 2)- explain one difference between the federal, state, and local governments. ( question 3)- explain one similarity between the federal executive branch and the state executive branch. ( question 4) - explain one difference between the federal executive branch and the state executive branch. (question 5) - explain one similarity between the federal legislative branch and the state legislative branch. ( question 6) - explain one difference between the federal legislative branch and the state legislative branch. ( question 7) - explain one similarity between the federal judicial branch and the state judicial branch. ( question 8) - explain one difference between the federal judicial branch and the state judicial branch.