What caused early humans to first migrate out if africa?

Why did separate government develop in ancient greece?

Pls will give brainliest and 5star asap pls

Which event was one of the greatest factors that led to massive emigration from ireland to the united states in the mid-1800s? a) world war i b) the civil war c) the irish potato famine d) colonization of the new world plz fastest and right answer gets 94 !