The U. S. paid to for the upper portion of California and parts of New Mexico.
a.
nothing, anyone
b.
$5 million, U. S. citizens
c.
$10 million, Texas
d.
$15 million, Mexico

I think it's d. $15 million to Mexico

Explanation:

I remember that the U.S was paying off the settler's claims to the land. Might want to check this, however.

one of the main reasons was definitely slavery. back in 1861, republican abraham lincoln was elected and ended up being a major influence in the slavery business. slavery greatly affected the texas economy because back in 1845 during the annexation of texas, slaves became a big part of the texas population. many texans that were in favor of the secession influenced groups through party ties.

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