Which is one way that the Neolithic Revolution contributed to the
development of ancient river valley civilizations?

A. As humans developed agriculture, they were able to stop following
herds of animals and build towns and cities.

B. As people moved from place to place hunting animals and
gathering wild plants, they built small cities at each place they
stopped.

C. River valley civilizations grew as people gathered to trade the
animals they hunted and wild plants they gathered.

D. River valley civilizations grew because people needed to defend
themselves from growing groups of nomadic warriors.​