| A | B |
|---|
| abiotic | describes nonliving factors in the environment |
| biome | a large region characterized by a specific type of climate and certain types of plant and animal communities |
| savanna | a tropical grassland biome with scattered clumps of trees |
| desert | a hot, dry biome inhabited by organisms adapted to survive high daytime temperatures and long periods without rain |
| tundra | a far-northern biome characterized by long, cold winters, permafrost, and few trees |
| permafrost | the permanently frozen ground just below the surface of the soil in the arctic tundra |
| marine | an ecosystem based on salty water |
| phytoplankton | microscopic photosynthetic organisms that float near the surface of the ocean |
| zooplankton | very small animals that, along with the phytoplankton they consume, form the base of the oceans' food web |
| estuary | an area where fresh water from streams and rivers spills into the ocean |
| tributary | a small stream or river that flows into a larger one |
| littoral zone | the zone of a lake or pond closest to the edge of the land |
| open-water zone | the zone of a lake or pond that extends from the littoral zone out across the top of the water and that is only as deep as light can reach through the water |
| deep-water zone | the zone of a lake or pond below the open-water zone, where no light reaches |
| wetland | an area of land where the water level is near or above the surface of the ground for most of the year |
| marsh | a treeless wetland ecoysystem where plants such as cattails and rushes grow |
| swamp | a wetland ecosystem where trees and vines grow |
