Question

Agricultural techniques like irrigation could help a civilization expand its borders because they could use irrigation to:

A.lessen the threat of flooding by spreading the water thin.
B.protect their cities by building defensive dams and dikes.
C.develop more land that was previously too dry for farming.
D.send convoys to conquer areas previously unreachable by land.

Answer 1

C probably, because it's the only one that seems to show how they can expand borders. D is quite good but it's not related to irrigation.