Methanogens are archaebacteria, abundant in cattle yard and paddy fields.

Correct Option: B

Methanogens are archaebacteria, abundant in cattle yard and paddy fields.

Eubacteria are prokaryotic but eubacteria are enclosed by plasma membrane like eukaryotic cells.

Correct Option: A

Eubacteria are prokaryotic but eubacteria are enclosed by plasma membrane like eukaryotic cells.

Autotrophs are those organisms that are able to make energy-containing organic molecules from inorganic raw material by using basic sunlight. Nostoc, Chara, Porphyra and Wolffia are photoautotrophs while Nitrosomonas and Nitrobacter are chemoautotrophs.

Correct Option: C

Autotrophs are those organisms that are able to make energy-containing organic molecules from inorganic raw material by using basic sunlight. Nostoc, Chara, Porphyra and Wolffia are photoautotrophs while Nitrosomonas and Nitrobacter are chemoautotrophs.

Cyanobacteria are also referred as blue green algae, they perform oxygenic photosynthesis. They are most successful autotrophic organisms on earth which are
found in all types of environment - fresh water, sea water, salt marshes, moist rocks, tree trunks, moist soils, hot springs, frozen waters.

Correct Option: D

Cyanobacteria are also referred as blue green algae, they perform oxygenic photosynthesis. They are most successful autotrophic organisms on earth which are
found in all types of environment - fresh water, sea water, salt marshes, moist rocks, tree trunks, moist soils, hot springs, frozen waters.

The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the heterotrophic bacteria. Lactobacillis bacteria convert milk into curd.

Correct Option: D

The most abundant prokaryotes helpful to humans in making curd from milk and in production of antibiotics are the heterotrophic bacteria. Lactobacillis bacteria convert milk into curd.