- A Flagella, used for bacterial motility
- B Plasmids, small circular DNA molecules
- C Spores and crystals
- D Capsules, the protective outer layer
Correct answer: C. Spores and crystals
Explanation: Cry proteins (delta endotoxins) are stored as spore-crystal complexes in Bacillus thuringiensis. The crystalline inclusions are released and activated in the insect gut.
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers