Which invention was in use before the Second Industrial Revolution?

The formation of business monopolies in the late 1800s was made possible by the (1) effects of laissez-faire policies (2) passage of federal antitrust laws (3) elimination of the free-enterprise system (4) adoption of socialist economic practices

How did the invention of the cotton gin affect slave labor in the united states? a. there was a forced migration of slaves from the south to the north. b. slave-owning cotton planters were gradually forced to sell their plantations. c. more slaves were purchased to work on cotton plantations in the south. d. the reduced need for labor on cotton plantations led to a decline in slavery. e. slaves were moved from cotton plantations to sugar plantations.

What was the focus of the stanford study-pls