Exploration of antarctica’s interior did not begin until a treaty was signed by 12 nations airplanes were strong enough to withstand the winds and cold tractors were brought to the continents sailors from european countries landed on pack ice

Match these items. 1 . stephen douglas published "north star" 2 . frederick douglass first african slaves arrived in jamestown 3 . crittenden compromise proposed kansas-nebraska act 4 . republican party extend 36° 30' line to california 5 . abolitionists servitude in exchange for passage to the united states 6 . indentured struggle between proslavery and antislavery groups 7 . jefferson davis formed to prevent spread of slavery 8 . "bleeding kansas" wanted slavery abolished 9 . uncle tom's cabin president of confederacy 10 . 1619 harriet beecher stowe