Sequence the principal stages of biological nitrogen fixation in their correct order of occurrence:
(A) Formation of infection thread
(B) Rhizobiummultiply to colonize
(C) Curling of root hair
(D) Differentiation of cortical cells into nitrogen-fixing cells
Choose the correct answer from the options given below:

Correct option is A

· Nitrogen fixation is a biological process in which leguminous plants and Rhizobium bacteria form a symbiotic relationship to fix atmospheric nitrogen.
· The correct sequence of events is:
1. (B) Rhizobium bacteria multiply and colonize the rhizosphere.
2. (C) Root hair curls to trap bacteria, facilitating entry.
3. (A) Formation of the infection thread, through which bacteria enter root cells.
4. (D) Cortical cells differentiate into nitrogen-fixing cells, forming root nodules that fix nitrogen into a usable form for plants.