The shortage of workers to grow cash crops such as cotton in the
Americas led to - *

Slavery

Explanation:

In the Americas, in the Southern Colonies, cotton was one of the cash crops of the British Colonies. So was tobacco, indigo, and rice.

Indentured servants were the main source of labor, but they only worked for seven years before they were free. In addition, indentured servants were like normal people and received much better condition than those of the slaves later on.

Because the English were always trying to get ways of cheap labor and they were in a relationship with Africa, they resolved to slavery.

Slavery had begun with Native Americans, but they were too unfit for the labor. They died from diseases, as they were not immune—as opposed to the British who were.

So began the Atlantic Slave Trade—the trade of African peoples for firearms for defense between African tribes.

c) the invasion of the shang