The life sustaining zone of earth, where lithosphere, hydrosphere and atmosphere interact is called :

Among the following which is a nitrogen fixing bacteria ?

Name the organism which is involved in denitrification ?

One gallon is equivalent to :

Study of inter-relationship of organs and their environment is called :

Which is the biggest storehouse of water ?

Name the process in which the ammonia is converted into nitrites and nitrates ?

When the plants and animals die, their protein convert into ammonia by the action of bacteria are called :

The organism and the physical environment of the habitat form an ecological complex called :

During photosynthesis which gas is liberated in the atmosphere ?