When the united states decided to build a canal across central america, panama was

part of Colombia

Panama was a department of Colombia for 80 years after achieving its independence from Spain. The territory had joined voluntarily at the end of 1821.

However, there had been several attempts at secession. The United States was interested in the area as they were considering building the Panama Canal. When the Senate of Colombia rejected a treaty with the U. S. that would have enabled the construction of the project, the United States decided to encourage independence.

Panama declared its independence in November 1903, and granted rights to the United States to build the canal, administer it, fortify it and defend it "in perpetuity."

the second significant cause of the great migration was the desire of black southerners to escape segregation, known euphemistically as jim crow. rural african american southerners believed that segregation - and racism and prejudice against blacks - was significantly less intense in the north.

just finished this it is b. centrifugal force