What is true about Bt-toxin ?

detailed solution

Correct option is B

Bt toxin is produced by a bacterium called Bacillus thuringiensis (Bt for short). B. thuringiensis forms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein. Actually, the Bt toxin protein exists as inactive protoxins but once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilises the crystals.