Ecological Systems, Closed

**Definition:** Systems that provide for the maintenance of life in an isolated living chamber through reutilization of the material available, in particular, by means of a cycle wherein exhaled carbon dioxide, urine, and other waste matter are converted chemically or by photosynthesis into oxygen, water, and food. (NASA Thesaurus, 1988)

**Tree numbers:** - G16.500.275.157.240 - N06.230.124.240 - N06.230.150.225

**Synonyms:** - Closed Ecological Systems