Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Bacillus thuringiensis strains do not kill themselves despite producing insecticidal protein crystals. Reason (R): The Bt toxin protein exists as an inactive protoxin that requires an acidic pH, which is only found in the insect gut, to become active. In the light of the above statements, choose th

Step-by-step solution

Assertion (A) is correct because the Bt toxin protein exists as an inactive protoxin in the bacteria, which is why it does not kill the Bacillus thuringiensis strains that produce it. Reason (R) is incorrect because the inactive protoxin requires an alkaline pH, not an acidic pH, to become active. The alkaline pH of the insect gut solubilises the protein crystals, converting them into the active toxin. Therefore, Assertion is correct but Reason is not correct. Answer: Assertion is correct but Reason is not correct.