What triggers activation of protoxin to active Bt toxin of Bacillus thuringiensis in boll worm?

(A)Body temperature
(B)Moist surface of midgut
(C)Alkaline pH of gut
(D)Acidic pH of stomach

The NCERT line that answers it

Verbatim line

Actually, the Bt toxin protein exist as inactive *protoxins* but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals.

Chapter: Biotechnology and its Applications
Section: 10.1 BIOTECHNOLOGICAL APPLICATIONS IN AGRICULTURE
Page: 2
Words matched: 38 of 38

The answer appears as a continuous sentence in NCERT. This is that sentence.

How this line gives the answer

0, emb=1.0, combined=1.0). Verified: high — The span explicitly states that the protoxin is converted to active toxin due to the alkaline pH of the gut, which directly matches and distinguishes the correct answer (C) from the wrong options.

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