absolutely indispensable, essential.
The electromagnetic wavelength range between 100 nm and 1 mm is referred to as optical radiation. By definition, this includes ultraviolet radiation (UV), the visible light spectrum (VIS) and infrared radiation (IR).
Organic compounds are substances composed primarily of hydrogen (H) and carbon (C). Organic chemistry is concerned with the properties, composition and production of carbon compounds.
An organism is an individual life form - see living organism.
Oxidation generally refers to the chemical process in which an element reacts with oxygen or in which electrons are lost.
Symbol O2 - Oxygen is the most common element on Earth. As molecular oxygen, it is an odourless, colourless gas. Oxygen occurs primarily in combination with other elements such as hydrogen (to form water); air is approx. 20% oxygen by volume.