Name a fern that fixes the atmospheric nitrogen and descibe it.

Choose correct statement(s) about ''Azolla': (I) Azolla is a free-floating water fern. (II) Azolla fixes the atmospheric nitrogen in association with nitrogen fixing blue green alga Anabaena azollae. (III) It is used as a bio-fertilizer for wetland rice cultivation. (IV) Not suitable for rice crop.

Define one atmosphere.

What is atmosphere?

Bacteria that can fix atmospheric nitrogen while free living in the soil is

When CaC_2 is heated in atmospheric nitrogen in an electric furnace the compound formed is

Study the following statements and select the correct ones (i) Methanogens are archeabacteria which produce methane in marshy areas (ii) Nostoc is a filamentous blue green alga which fixes atmospheric nitrogen. (iii) Many members of the genus Glomus form mycorrhiza.

Name the process of conversion of nitrates to atomospheric nitrogen.