Answer:
The correct answer will be- all options are correct.
Explanation:
Azotobacter is a genus or a group of bacteria which are involved in the process of nitrogen fixation.
The bacteria can be easily identified by their rod-shaped form and gram staining. Gram staining results show that they are gram-negative bacteria as they stain pink in color due to the thin peptidoglycan layer.
They require oxygen to perform cellular respiration so are called obligate aerobes. Also, they can fix the atmospheric nitrogen by converting it into ammonia.
Thus, all the options are correct.
