Rhizobium are helpful to a plant because. A.) They provide glucose for the plant.

B.) They help the plant photosynthesize.

C.) They deliver usable nitrogen to the plant's roots.

D.) They can convert atmospheric carbon dioxide into a usable form for
photosynthesis.

Option C

Explanation:

Rhizobium is a variety of microorganisms related with the development of root knobs on plants. These microscopic organisms live in beneficial interaction with vegetables. They take in nitrogen from the air and give it to the plant, permitting it to fill in soil low in nitrogen.

where is the scientific experiment?

the correct answer is b