Answer: Alkaline pH of the insect gut along with gut proteases dissolve the crystals.
- A Acidic pH of the insect gut directly dissolves the protective protein crystals over time
- B Alkaline pH of the insect gut along with gut proteases dissolve the crystals
- C Insect digestive enzymes acting at a neutral gut pH alone, independent of pH level
- D High temperature within the insect gut directly denatures the protective outer coat
Correct answer: B. Alkaline pH of the insect gut along with gut proteases dissolve the crystals
Explanation: The alkaline pH of the insect midgut, combined with gut proteases, dissolves the crystalline inclusions and activates the pro-toxin cry proteins into active toxins that bind to midgut epithelial cells, causing cell lysis and death.
Sewage passes through physical removal (primary), then aerobic biological treatment where microbes form flocs that consume organic matter (secondary); the settled activated sludge is then digested anaerobically to produce biogas - a deliberate switch from aerobic to anaerobic conditions between stages.
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers