Final answer:
Studying insecticide exposure on humans is more complicated than on laboratory animals due to variations in metabolism, collateral damage, and the disruption of hormones.
Step-by-step explanation:
Studying insecticide exposure on humans is more complicated than studying it on laboratory animals due to several factors. First, individuals vary in their capacity to metabolize and resist the effects of insecticides, which can lead to different responses in humans. Second, humans compete for food with crop pests, and pesticides used to control these pests can have collateral damage and health risks. Third, the arrival of chemicals capable of disrupting hormone action has raised concerns in toxicology research.