1) Methanogens and fermenter bacteria are known for their syntrophic metabolic model because fermenters break down complex organic compounds/acetate/methane/carbon dioxide/hydrogen sulfide into H2, and carbon dioxide/methane & hydrogen sulfide/methane & carbon dioxide , which are then used by methanogens for the production of  methane/hydrogen sulfide/ acetate .2) All methanogens are Archaea.Select one: True/ False3) All microbes found from Yellowstone’s hotsprings were Archaea.Select one: True/ False4) Choose the best definition of biofilm and why its formations are significant in understanding Archaea. a. Biofilms are transparent layers of cellulose that protects Archaea from UV.b. Biofilms are agglomerations of multiple cells and exopolymers that allow microbes to adhere to host cell surfaces.c. Biofilms are thin planes of microbial cells connected together to make a one-cell thick layer that is impenetrable to antibiotics.d. Biofilms are communities of microbes that have syntrophic metabolic pathways.5) In Samuel and Gordon (2006)’s study, the inoculation of germ-free mice with  Bacteriodetes thetaiotaomicron and Methanobrevibacter smithii/ Bacteriodetes thetaiotaomicron alone/ Methanobrevibacter smithii alone/ Bacteriodetes thetaiotaomicron and Desulfovibrio piger/ Desulfovibrio piger alone/ Methanobrevibacter smithii and Desulfovibrio piger leads to the greatest digestion short-chain fatty acids and consequently, the greatest  absorption of food/ biofilm production/ level of depression/ sulfate reduction .