Characteristics of various ocean zones, including variations in ocean temperature, salinity, and depth are discussed. The different groups of marine life and adaptations of plants and animals are highlighted. Estuaries and various freshwater environments, such as streams, rivers, ponds, and lakes are also explored. Other terminology includes: aquatic, sea anemone, benthos, plankton, nekton, intertidal zone, neritic zone, open ocean, running water, standing water, and biological productivity.