Europe has a challenging geography which makes it difficult to grow crops

What river valley civilization in the plow

This term refers to the number of people per unit area (usually a kilometer or a mile). this could refer to the number of people per square mile in a city, a county, a province, a state, or a nation.

What new form of music swept the nation in the 1950s a. chamber music b. hip-hop c. jazz d. rock-and-roll