Which ruler declared himself the first sultan of the Delhi sultanate?

In 1206, Qutb ud-Din, one of his generals, proclaimed himself sultan of Delhi and founded a line of rulers called the Slave dynasty, because he and several of the sultans who claimed succession from him were originally military slaves.

Explanation:

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.