Question

some bacteria live in the roots of plants like soybeans and peas. what is the role of these bacteria in the nitrogen cycle? to absorb nitrogen - containing compounds from the soil to release free nitrogen into the atmosphere to break down nitrogen - containing compounds in dead organisms to convert free nitrogen into usable nitrogen

Explanation:

Plants cannot directly use free nitrogen (\(N_2\)) from the atmosphere. Bacteria in the roots of legumes (like soybeans and peas) perform nitrogen - fixation. Nitrogen - fixation is the process of converting free nitrogen (\(N_2\)) into ammonia (\(NH_3\)) or other usable nitrogen - containing compounds (such as nitrates \(NO_3^-\)) that plants can absorb and use for growth.

• Absorbing nitrogen - containing compounds from the soil is the role of plant roots, not these bacteria.
• Releasing free nitrogen into the atmosphere is the role of denitrifying bacteria, not the bacteria in legume roots.
• Breaking down nitrogen - containing compounds in dead organisms is the role of decomposer bacteria (like ammonifying bacteria), not the bacteria in legume roots.

Answer:

to convert free nitrogen into usable nitrogen