3. which of the following statements is true regarding the construction of the transcontinental railway?
a. the sierra nevadas were the most difficult obstacle for the union pacific railroad.
b. construction began in omaha, nebraska, in 1863 and in sacramento, california, in 1865.
c. most workers for the union pacific railroad were chinese.
d. most workers on the central pacific leg of the railway were chinese.

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.