sentence2_structure: Living things on the ocean floor<>are known<>as benthos
sentence1: Biogeographic provinces could be the basis for a primary choice of sampling strata, although these are not absolute in character because phytoplankton are affected by climate and latitude, zooplankton by ocean circulation and fronts, and benthos by depth and the nature of the sea floor.
sentence2: Living things on the ocean floor are known as benthos.
question: Living things on the ocean floor are known as?