Indicate if each of the following descriptions matches lithotrophic (L), organotrophic (O), or phototrophic (P) organisms. Your answer would be a four-letter string composed of letters L, O, and P only, e.g. LLPP.
( ) They feed on other living organisms or their organic products.
( ) They are responsible for the current oxygen-rich atmosphere of the Earth.
( ) They are all known to be prokaryotic.
( ) They are the primary energy converters in hydrothermal vents in the ocean floor.