Which phenomenon describes light produced by living organisms?

Bioluminescence is the phenomenon where light is produced by living organisms. This process occurs due to biochemical reactions within these organisms, typically involving a light-emitting molecule called luciferin and an enzyme called luciferase. Many organisms exhibit bioluminescence, including certain species of jellyfish, fireflies, and deep-sea creatures.

Bioluminescence serves various ecological purposes, such as attracting mates, deterring predators, and luring prey. It is distinct from other forms of light production, such as chemiluminescence, which refers to light produced through a chemical reaction but is not specifically linked to living organisms. Fluorescence involves light absorption followed by re-emission, often after a brief delay, while incandescence refers to light produced due to high temperatures, such as with a typical light bulb or burning materials. Thus, bioluminescence is unique to biological systems, making it the correct answer for this phenomenon.