Where does nitrogen from the atmosphere go before it enters a plant?

A. The nitrogen fixes into carbon dioxide.

B. The nitrogen goes into the nodules of the plant.

C. The nitrogen atoms of the atmosphere never enter the plant.

D. The nitrogen goes through the roots into the soil.

Answer: B. The nitrogen goes into the nodules of the plant.

Explanation:

The atmospheric nitrogen is not directly absorbed by the plants. In plants there are root nodules which in the absence of nitrogen in the soil develops a symbiotic association with the nitrogen fixing bacteria (eg. Rhizobia). This process can be seen among the leguminous plants like beans, soyabean and pea. Inside the root nodules the host specific bacteria fixes the atmospheric nitrogen in the form of usable compounds like ammonia, which is utilized in the production of the amino acids (the building blocks of proteins), nucleic acids (DNA, and RNA), energy molecules of ATP, and other cellular components like hormones, flavones and vitamins.

The anwser is the nitrogen goes ininto the nodules of the plant