1. The biological factors acting on an organism, which arise from the activities of other living organisms, as distinct from physical factors.
2. The living organisms of a community habitat or environment.

1. The radio-frequency field or fields existing in a given area or desired in an area to be shielded.
2. The resulting product of the power and time distribution, in various frequency ranges, of the radiated or conducted electromagnetic emission levels that may be encountered by a military force, system, or platform when performing its assigned mission in its intended operational environment.

It is the sum of electromagnetic interference; electromagnetic pulse; hazards of electromagnetic radiation to personnel, ordnance, and volatile materials; and the natural phenomena effects of lightning and precipitation static.

The physical conditions that characterize the mouth of a river where it connects with the open sea and fresh water mixes with salty ocean water.

The regions of the earth that include the oceans and seas: The marine environment takes up about three-fourths of the earth's surface all of which has a system of tides and waves, a high saline content, a variety of life forms, and includes bays and estuaries as well as other major bodies of water.

1. An environment which keeps the body temperature at an maximum point at which the least amount of oxygen is consumed for metabolism.
2. The environment which enables a neonate (newly born child) to maintain a body temperature of 97.7° F (36.5° C) with a minimal requirement of oxygen and energy.

Living and thriving in an environment that has significant periodic changes of light, temperature, and moisture.