Question

1. in what ways is n₂ gas removed from the atmosphere?
2. name 3 types of bacteria involved in the nitrogen cycle.
3. by what process are animal wastes, urine and dead organisms converted to other nitrogen containing compounds?
4. what is the only form of nitrogen that non - legume plants can take in and use?
5. what do the denitrifying bacteria do?

Explanation:

1. Nitrogen gas ($N_2$) is removed from the atmosphere mainly through nitrogen - fixation by bacteria (such as Rhizobium in root nodules of legumes), lightning which causes nitrogen and oxygen to react, and industrial processes like the Haber - Bosch process.
2. Three types of bacteria involved in the nitrogen cycle are nitrogen - fixing bacteria (e.g., Rhizobium), nitrifying bacteria (which convert ammonia to nitrites and then nitrates), and denitrifying bacteria (which convert nitrates back to nitrogen gas).
3. Animal wastes, urine, and dead organisms are converted to other nitrogen - containing compounds through the process of decomposition. Decomposer bacteria and fungi break down the organic matter and release ammonia in a process called ammonification.
4. Non - legume plants can take in and use nitrate ($NO_3^-$) as the main form of nitrogen.
5. Denitrifying bacteria convert nitrates ($NO_3^-$) into nitrogen gas ($N_2$), returning it to the atmosphere and completing the nitrogen cycle.

Answer:

1. Nitrogen - fixation by bacteria, lightning, industrial processes.
2. Nitrogen - fixing bacteria, nitrifying bacteria, denitrifying bacteria.
3. Decomposition (ammonification).
4. Nitrate ($NO_3^-$).
5. Convert nitrates ($NO_3^-$) into nitrogen gas ($N_2$).