Did the ancient greece invented math? (p. s.if you find any good facts about ancient greece it would really ^_^)

How has the immigration of the 1990s affected the social and economic life of the united states?

Which groups of people most directly benefited from song innovations in the song dynasty‘s open border policy?

Using mr smith and his id, identify two potential internal validity threats that might affect the a—b design. tell me how that threat might impact conclusions in the a—b design. note #1: you cannot use maturation (since i already did that one for note #2: there are some mr smith id threats that won’t have much impact in a single case design.