Definition: A depression caused by erosion by water or ice. Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet.
Definition: A mixed forest biome is a forest biome which contains densely packed populations or communities of broadleaf and coniferous trees, strongly limiting light penetration to the forest floor.
