A millibar is a unit of pressure which is most commonly seen in the context of meteorology, where atmospheric pressure is sometimes given in millibars. As the name would suggest, a millibar is equal to one thousandth of a bar.
User: The microscopic organisms at the base of the marine food chain are known as A. plant life. B. terrestrial animals. C. primitive life. D. phytoplankton. Weegy: The microscopic organisms at the base of the marine food chain are known as Phytoplankton. User: In addition to being necessary for respiration, _______ also provides UV radiation protection. A. water B. hydrogen C. oxygen D. carbon dioxide.
Plankton consisting of free-floating algae, protists, and cyanobacteria. Phytoplankton form the beginning of the food chain for aquatic animals and fix large amounts of carbon, which would otherwise be released as carbon dioxide.