Why is the precambrian not divided into many time subdivisions whereas the paleozoic, mesozoic and cenozoic are?

What is guaranteed by the 5th amendment

Using complete sentences, compare and contrast the leadership and accomplishments of martin luther king, jr. and frederick douglass.

European imperialism in the 19th century was largely motivated by a desire to: o a. assert power over other parts of the world. b. end the racist policies practiced in many foreign countries. o c. defend europe from aggressive foreign armies. d. relocate ethnic and religious minorities within national borders.