A farmer uses triazine herbicide to control pigweed in his field. For the first few years, the triazine works well and almost all the pigweed dies; but after several years, the farmer sees more and more pigweed. Which of these explanations best explains what happened?

Question

Quizplus · Accepted Answer

Over time, the repeated use of triazine herbicide has selected for pigweed individuals with a natural resistance to the herbicide. These resistant individuals were then more likely to survive and produce offspring with the same resistance, leading to a population of pigweed that is increasingly resistant to triazine.

A Farmer Uses Triazine Herbicide to Control Pigweed in His