OpenSimulator Archive. OAR file is an OpenSimulator Archive. OpenSimulator is an open source multi-platform, multi-user 3D application server. It can be used to create a virtual environment (or world) which can be accessed through a variety of clients, on multiple protocols.
biological adaptation the adaptation of living things to environmental factors for the ultimate purpose of survival, reproduction, and an optimal level of functioning. color adaptation. 1. changes in visual perception of color with prolonged stimulation.
Medical Definition of BIOCHEMICAL OXYGEN DEMAND. : the oxygen used in meeting the metabolic needs of aerobic microorganisms in water rich in organic matter (as water polluted with sewage)âcalled also biological oxygen demand, oxygen demand. Britannica.com: Encyclopedia article about biochemical oxygen demand.noun biochemical oxygen deÂ·mand \-di-Ëmand\. : the oxygen used in meeting the metabolic needs of aerobic microorganisms in water rich in organic matter (as water polluted with sewage)âcalled also biological oxygen demand, oxygen demand.efinition of BIOCHEMICAL OXYGEN DEMAND. : the oxygen used in meeting the metabolic needs of aerobic microorganisms in water rich in organic matter (as water polluted with sewage). ADVERTISEMENT. noun biochemical oxygen deÂ·mand \-di-Ëmand\.