NEET Zoology Question (2026) — Solution

Step-by-step solution

Bt toxin is produced by the bacterium Bacillus thuringiensis in an inactive form called protoxin. When an insect ingests this inactive toxin, it enters the gut where the pH is alkaline. The alkaline pH of the insect gut solubilizes the protein crystals, converting the inactive protoxin into its active form. The active toxin then binds to the surface of midgut epithelial cells, creating pores that cause cell swelling and lysis, eventually leading to the death of the insect. Answer: due to alkaline pH