Answer:
The Cataracts of the Nile are shallow lengths (or whitewater rapids) of the Nile River,
Explanation:
The Cataracts of the Nile are shallow lengths of the Nile River, between Khartoum and Aswan, where the surface of the water is broken by many small boulders and stones jutting out of the river bed, as well as many rocky islets.
