Beginning with the efforts of John Rolfe, colonists in Jamestown began producing and selling what product to England for a profit?

Rolfe was the first to see tobacco as a cash crop. He (and other colonists) in the Jamestown plantation began using tobacco as a marketable crop that brought in great profits for the inhabitants of the colony. It was found, after trials among the plantation dwellers and being shipped to England, that the plant was a better variety than that created in Spain, so the Virginia variety became the go-to choice.