A result of volcanic eruptions in the Cascade Range is that A. large numbers of people have settled in the region.
B. the possibility of long-lasting droughts has grown.
C. some residents in the region have lost their lives.
D. the opportunities for jobs in the region has grown.

some resident in the region have lost their lives

c it says nothing about connecting those 2 seas.

while it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton.

explanation:

before eli whitney's invention of the cotton gin, picking and cleaning cotton was a slow, labor-intensive job. workers, usually slaves, had to pick the seeds from the cotton fibers by hand. this invention made it possible to grow large amounts of cotton on big farms and make money.