Which of the following contributions was made by the cotton gin?

The invention of the cotton gin by Eli Whitney in 1793 dramatically transformed the cotton industry in the United States. This machine efficiently separated cotton fibers from their seeds, an arduous task that had been performed by hand and was labor-intensive. As a result, the volume of cotton that could be processed increased significantly, leading to a notable rise in the amount of cotton produced daily.

This increase in production had far-reaching economic implications. Cotton became a major cash crop and drove the growth of the American economy in the early 19th century, particularly in the Southern states, where cotton plantations expanded rapidly. The enhanced efficiency of cotton processing helped solidify cotton's status as a dominant force in American agriculture, fueling both local economies and international trade.

In contrast, the other options do not accurately reflect the primary impact of the cotton gin. It did not contribute to transportation speed, nor did it directly create jobs for skilled artisans since the demand for manual labor increased instead. Additionally, the establishment of time zones is unrelated to the function or impact of the cotton gin, stemming from advancements in transportation and railroads later in the 19th century.