Question

Arrange the sequence of the development of root nodules. 

I. Chemical recognition. 

II. Nodule formation. 

III. Curling of root hair. 

IV. Formation of infection thread.

Choose the correct option. 

(a) I – II – III – IV 

(b) I – III – IV – II 

(c) I – IV – III – II 

(d) IV – I – III – II

Answer 1

Correct option: (b) I – III – IV – II

The sequence of development of root nodules is as follows Chemical recognition – curling of root hair – formation of infection thread – nodule formation.

During N₂-fixation roots of the legumes and Rhizobium bacteria interact with each other. As a result of these nodules are formed.