What has been the general pattern in life expectancy during the 20th century with respect to men and women?

Explanation:

In the first half of the 20th century women had the advantage. They gained more expectancy than men had. While in the later part of the century men are making better gains than women and this has narrowed down the gap that was once large. In the pattern has been clear in the first half women had more and in the second half the gap in reducing.

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.