Within a decade of the introduction of a new insecticide nearly all of the descendants of the target pests were immune to the usual-sized dose the most likely explanation for this immunity is that?

Answer 1

Natural selection is one way to explain it. When the survivals of the insecticide reproduced, the gene that allowed them to live was passed on. In time, the gene was spread throughout the entire population and every member of the pest became immune.

Answer 2

The pests likely developed resistance through genetic mutations that made them less susceptible to the insecticide. The repeated exposure to the insecticide allowed only the resistant individuals to survive and reproduce, passing on their resistance to future generations. This process is known as natural selection.