Which sentence from the section shows HOW the Pax Mongolica made the Silk Road better?

Sparta faces threats from without and within the city-state who posed these threats.

Which is not a claim kennedy made? a. the fact that communist cuba is so close to american soil is one reason we need to accelerate our space program. b. his decision to shift the study of space to one of the highest american priorities was one of his most important decisions as president. c. within these last months at least 45 satellites have circled the earth. (i think it's this one) d. the mariner spacecraft now on its way to venus is the most intricate instrument in the history of space science. i need this answer really quick, so .

In what is known as the great migration, large numbers of african americans moved from the rural south to northern cities, beginning in the early twentieth century. what motivated this large-scale movement?