| ECOLOGICAL SYSTEM |
| A habitable environment, either created artificially, such as in a manned space vehicle, or occuring naturally, such as the environment on the surface of the earth, in which man, animals, or other organism can live in mutual relationship with each other. Ideally, the environment furnishes the sustenance for life, and the resulting waste products revert or cycle back into the be used again for the continnuous support of life. |