Some strains of Bacillus thuringiensis produce proteins that can not kill:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Hymenopterans
Bt toxin is a protein made by the bacterium Bacillus thuringiensis. It lies in the bacterium as an inactive protoxin. When an insect eats it, the alkaline gut turns it into the active toxin. The active toxin makes holes in the cells of the gut wall, and the insect dies. Each Bt toxin kills only a certain group of insects.
(1) Coleopterans — Killed by Bt toxin. This group includes beetles.
(2) Dipterans — Killed by Bt toxin. This group includes flies and mosquitoes.
(3) Hymenopterans — Not killed by Bt toxin. This group (bees, wasps, ants) is not among the insect groups that Bt proteins kill.
(4) Lepidopterans — Killed by Bt toxin. This group includes the tobacco budworm and the armyworm.
Note: A similar question was also asked in CUET (UG) 2026 on 21-05-2026 (Slot 2), and in CUET (UG) 2025 on 14-05-2025 (Slot 2).
NCERT Extract:
Biotechnological Applications in Agriculture – …
