| A | B |
|---|
| biome | a major land ecosystem having a distinct combination of plants and animals |
| tundra | a biome characterized by cold temperatures and low precipitation |
| taiga | a biome that contains many coniferous trees and in which rainfall is moderate |
| deciduous forest | a biome that contains many trees, four distinct seasons, and in which rainfall is moderate |
| grassland | a biome containing many grasses but few trees and having low to moderate rainfall |
| tropical rain forest | a biome distinguished by lush vegetation, abundant rainfall, and plentiful sunlight |
| desert | a biome in which plant life is not abundant and rainfall is low |
| river | a freshwater ecosystem characterized by running water |
| lake | a freshwater ecosystem characterized by still, or standing water |
| wetland | any one of three ecosystems-marsh, swamp, or bog-where land and freshwater meet |
| shoreline | an ecosystem where land and ocean meet |
| coastal ocean | a saltwater ecosystem that is relatively shallow and close to the shoreline and that supports an abundance of life |
| open ocean | a large saltwater ecosystem containing both floating and free swimming organisms |
| biodiversity | the great abundance of different life forms in an ecosystem |
| threatened | species that are in danger of becoming endangered |
| endangered | the numbers of a species are getting dangerously low and are in danger of extinction |
| extinct | total destruction of a species, there are no more |
