How do scientists estimate when humans reached a new area?

they dig up fossils that looks like human remains ( bones )

Explanation:

jim crow law, in u.s. history, any of the laws in which racial was enforced, in the south between the finish of reconstruction in 1877 and the start of the social liberties development during the 1950s.

jim crow was the name of a minstrel routine( jump jim crow) performed starting in 1828 by its creator, thomas dartmouth ("daddy") rice, and by numerous imitators, including on-screen character joseph jefferson.

the term came to be a defamatory sobriquet for african americans and an assignment for their segregated life. the segregation rule was stretched out to parks, graveyards, theaters, and eateries with an end goal to keep any contact among blacks and whites as equivalents.

it was classified on neighborhood and state levels and most broadly with the "separate yet equivalent" choice of the u.s. preeminent court in plessy v. ferguson (1896).