In the early 1850s, with the westward movement, the slavery issue became a serious political issue endangering the unity of the country because ___.
A.whether the future states formed as aresult of the west ward movement should be free or slave world affect the balance of power in the Senate B.the southin sisted that slavery should beallowed tospread into all new territories C.the north refused to let slavery spread into new territories D.the north want edtoput and end to slavery正确答案A
