An incumbent is a current officeholder, running for re-election.
"<span>D. He was the first black man to be named a cabinet secretary" is not an accurate description of Benjamin Banneker. Banneker was an impressive and self-taught individual who corresponded with Jefferson and was fascinated with the world around him</span>
One of the central factors in the establishment of the trans-Saharan trade was "<span>b. The domestication of the camel," since only camels could survive the very long distances and extreme heat. </span>
