(singular: bacterium) single-celled organisms found in every ecosystem on Earth.
edge of land along the sea or other large body of water.
non-living organic material, often decomposing.
act in which earth is worn away, often by water, wind, or ice.
animal that is no longer a baby but has not reached sexual maturity.
type of tree or shrub with long, thick roots that grows in salty water.
organisms that travel from one place to another at predictable times of the year.
substance an organism needs for energy, growth, and life.
animal that hunts other animals for food.
part of a plant that secures it in the soil, obtains water and nutrients, and often stores food made by leaves.
solid material transported and deposited by water, ice, and wind.
bordering the tropics, just north of the Tropic of Cancer and south of the Tropic of Capricorn.
existing in the tropics, the latitudes between the Tropic of Cancer in the north and the Tropic of Capricorn in the south.