Concept:Rhizobium bacteria live in root nodules of leguminous plants and fix atmospheric nitrogen.
Explanation:Rhizobium enters the root hairs of leguminous plants and forms nodules.
Inside these nodules, it converts atmospheric nitrogen
N2 into ammonia
NH3 and other nitrogenous compounds that the plant can use.
This process naturally adds nitrogen to the soil.
Rhizobium does not add urea, decompose remains, or lower soil pH.
Answer:B. fixing atmospheric nitrogen into the soil