Question

3. Root nodules are not present on the roots of all the plants. How does the nitrogen fixation
occur in those plants which do not have root nodules?​

Answer 1

Answer:

Some nitrogen fixing bacterias are also in soil. They fix atmospheric nitrogen into nitrogenous compounds. Lightning contains nitrogenous compounds. When ligtning strikes, the nitrogenous compounds directly get into the soil. Plants uptake nitrogen from the soil and the plants are eaten by animals. When they excrete or die the nitrogenous compounds get into the soil and some nitrogenous compounds are converted into atmospheric nitrogen by some bacteria. Thus, it is called as nitrogen cycle.