Which statement best explains why the issue of slavery contributed to the outbreak of the civil war

Not sure which letter

Explanation:

The economies of the Confederate states relied on slave labor.

The economies of the Confederate states relied on slave labor.

Explanation:

Moral issues regarding slavery were seen as a major area of conflict between the states of north and south causing the civil war. But equally important is the economies of the slavery. The southern states want from the federal government to recognize the tradition of slavery as it was seen important for the southern economy. Moreover, they want to expand its westward whereas northern states want these territories for white labor.

The graph labeled aggregate emissions shows that pollution control methods are having a positive effect in the United States. The proof is a decreasing trend in this graph, with the percentage drop over this period reaching -63 %