What effect did it have on the Southern white society and economy?

The correct answer to this open question is the following.

Your question is incomplete. What do you mean by "it" in your question? You forgot to attach the element of reference.

However, trying to help you we can assume that the element that is missing is "the cotton gin."

If that is the case, then we can say the following.

The effect that it had on the Southern white society and economy was that the cotton gin revolutionized the way cotton was produced in the southern plantations and became one of the most important components of the strong economy in the South.

The immediate effect of the cotton gin on cotton production in the economy of the south in the early-1800s was the increase of cotton production.

One of the technologies that improved agriculture techniques in the United States during the 1790s, was the invention of the cotton gin by Eli Whitney. The year: 1793. This engine allowed farmers to separate the cotton fibers from the seeds in a quicker way, compared with the time it took slaves to do so. Landlords of large southern plantations increased the number of slaves when they realized they could produce more cotton to export with the use of the cotton gin and extra slaves.

the answer would be logic.

whole lotta ptsd going on