Which best compares the roles of nitrogen-fixing bacteria and certain decomposers in the nitrogen cycle? both organisms convert free nitrogen into nitrogen-containing compounds. both organisms convert nitrogen-containing compounds into free nitrogen. the bacteria convert free nitrogen into nitrogen-containing compounds, while the decomposers convert nitrogen-containing compounds into free nitrogen. the bacteria convert nitrogen-containing compounds into free nitrogen, while the decomposers convert free nitrogen into nitrogen-containing compounds.

The bacteria convert free nitrogen into nitrogen-containing compounds, while the decomposers convert nitrogen-containing compounds into free nitrogen.

Explanation:

Nitrogen is an essential element for all living organisms. It is required for synthesis protein and nucleic acids and other nitrogenous compounds. Some nitrogen fixing organisms such as Rhizobium, fixes atmospheric nitrogen (N₂) into usable forms such as nitrate (NO₃⁻) or ammonium (NH₄⁺ ) in the soil. The plants take up (NO₃⁻) and (NH₄⁺ )by absorption from the soil by their roots and make protein and nucleic acids.  Animals take up nitrogen by eating plants.  On death of a plant or animal and the nitrogenous waste produced by animals, decomposers such as bacteria and fungi convert this organic nitrogen into ammonium (NH4⁺) and later into NO₂⁻ and NO₃⁻. Denitrifying bacteria change NO₃⁻ into free nitrogen (N₂).