PLZ HELP!! Which best explains how rivers promoted the interaction between pre-historic groups?

A. They protected groups from invasion,

B. They allowed for easy movement to other regions,

C. they kept separate most of the time,

D. They let groups divide and form unique cultures.

In vernonia school district v. acton, the school district argued that a drug test was illegal under any circumstances. no student could refuse to take a drug test. drug tests were not given at random. drug testing was necessary to protect all students.

What did sargon's empire have in common with other mesopotamian city-states? a. it extended over a greater territory than anyone had ever conquered before. b. it fought with surrounding city-states. c. it covered an area from the mediterranean sea to the persian gulf. d. it had a professional army.

How do you think entrepreneurs contribute or industry in america? describe your answer