Which level of government has the greatest authority?

Assuming we are talking about US Government?

The Executive Branch has authority overall. All bills passed through Legislative still need to go to Excutive (president) to be signed or vetoed. However, the president cannot make laws so the Legislative branch is very powerful but does not have the greatest authority

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.