A large region characterized by a specific type of climate and certain types of plant and animal communities.

A region that has little or no vegetation, long periods without rain, and extreme temperatures.

The distance north or south from the equator.

A forest or jungle near the equator that is characterized by large amounts of rain and little variation in temperature and that contains the greatest known diversity of organisms of Earth.

A forest community characterized by cool, humid weather and abundant rainfall, where tree branches are draped with mosses, tree trunks are covered with lichens, and the forest floor is covered with ferns.

A community that is dominated by grasses, has few trees, and is characterized by cold winters and rainfall that is intermediate between that of a forest and a desert.

A forest that is characterized by trees that shed their leaves in the fall.

A region of evergreen, coniferous forest below the arctic and subarctic tundra regions.

A treeless plain that is located in the arctic or antarctic and that is characterized by very low winter temperatures, short cool summers, and vegetation that consists of grasses, lichens, and perennial herbs.

The height of an object above a reference point, such as sea level or the Earth's surface.

The layers of treetops that shade the forest floor.

The top foliage layer in a forest where the trees extend above surrounding trees.

A plant that uses another plant for support, but not for nourishment.

A plain full of grasses and scattered trees and shrubs found in tropical and subtropical habitats and mainly in regions with a dry climate, such as East Africa.

A foliage layer that is beneath and shaded by the main canopy of a forest.

The average weather conditions in an area over a long period of time.

An area that has a type of vegetation that includes evergreen shrubs and that is located in areas with hot, dry summers and mild, wet winters.