Answer:
Ecosystem.
Step-by-step explanation:
Archaea play an important role in ecosystems with organisms that derive or produce energy from oxidation of methane. Many of Archaea are bacteria which are often a major source of methane in such environments and they can play a role as primary producers. Archaea is important for scientists because it has unique ecological roles and can also generate energy differently i.e. responsible for producing biological methane which no eukaryotes or bacteria can do that.