Civilizations change and grow for a number of reasons: environmental change, new ideas, overpopulation, unreliable food sources, and even warfare. Which of these is a logical step for a civilization that has unreliable food sources?

lee and grant, both of whom held the highest rank in their respective armies, had known each other slightly during the mexican-american war (1846-48) and began their dialogue by exchanging awkward personal inquiries. characteristically, grant had arrived in his mud-splattered field uniform while lee had turned out in full dress attire, complete with sash and sword.

explanation:

north atlantic treaty organization.

b. martin luther king jr. wrote and spoke "i have a dream"

explanation:

i know this 100 percent is correct   b. is the best one. < 3

by 1880, germany had more rail lines than great britain and russia.