What is a push factor that might cause immigration

Which areas where seperated by the iron curtain

What happened 10 million years ago? if u answer, u get 50 ! plz answer ; -;

Alot of points! ! what was the greatest achievement of el libertador, simón bolívar? a. he became a military strongman in peru. b. he freed venezuelans from spanish rule. c. he bernardo o'higgins liberate chile. d. he united mexicans of all races against spain.