11. A stream in a bedrock valley located 5000 feet above ultimate base level that is draining a mountainous region in the headwater of a stream system would have a .

A stream in a bedrock valley located 5000 feet above ultimate base level that is draining a mountainous region in the headwater of a stream system would have a .

high gradient, and a narrow and shallow channel with no floodplain

Explanation:

A bedrock valley has no alluvium mantling the bedrock over which it flows. Alluvium (consists of sand, gravel, silt, clay, and gravel, as well as other organic matters) mantlings or coverings are usually developed in the lower part of the river with the formation of floodplains and deltas.  They may also be deposited at lakes or river banks.  Headwater streams deliver nutrients and other organic materials (e.g. fallen leaves) to downstream regions to sustain downstream aquatic life.