Explain how the expansion of slavery contributed to the ultimate dissolution of the union in 1860.

One of the primary reasons for the reinvigoration of slavery was the invention and rapid widespread adoption of the cotton gin. This machine allowed Southern planters to grow a variety of cotton - short staple cotton - that was especially well suited to the climate of the Deep South.

Explanation:

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.