Public concerns about Bt corn have included which potential risks discussed in the literature and media?

Introduction / Context:
Bacillus thuringiensis (Bt) transgenes confer insect resistance by producing Cry proteins toxic to specific pests. Alongside benefits, public debates have raised ecological and health-related concerns. Understanding these concerns helps contextualize risk assessment and biosafety studies.

Given Data / Assumptions:

• Historical reports discussed monarch butterfly exposure to Bt corn pollen on milkweed near fields.
• Food safety assessments have examined potential allergenicity of novel proteins.

Concept / Approach:
Risk assessment considers hazard identification and exposure. Cry proteins’ specificity reduces non-target risks, but early laboratory studies prompted field-scale evaluations for monarchs. Regulatory reviews also screen for allergenicity based on protein sequence, digestibility, and exposure data.

Step-by-Step Solution:

Verification / Alternative check:
Follow-up field studies generally found limited risk to monarch populations under typical field exposure, and regulatory reviews have not substantiated allergenicity in approved events; nonetheless, these were genuine public and scientific discussion points.

Why Other Options Are Wrong:

• Groundwater contamination is not a trait-specific Bt issue; it depends on agronomic practices.
• Complete reproductive isolation is false; Bt corn can cross with non-Bt corn without isolation measures.

Common Pitfalls:
Equating early laboratory findings with field outcomes; ignoring stewardship practices like refuge strategies to slow resistance.

Final Answer:
Both (a) and (b)