In functional allelopathy

A. Toxic substances are released as such from the plant

B. A precursor is released which is converted into active substances by some microorganisms

C. There is no question of release of any toxic substance

D. Release of nitrogen from nodule of legume take place

Answer: Option B

Solution(By Examveda Team)

Allelopathy is a common biological phenomenon by which one organism produces biochemicals that influence the growth, survival, development and reproduction of other organisms.
In functional allelopathy, a precursor is released which is converted into active substances by some microorganisms.