Question

Last year farmers discovered that a small amount of a new insecticide rapidly killed a worm species that was damaging their corn crops. The insecticide was so effective that they decided to use it again this year. They applied the same amount as last year, but it did not kill as many worms. What is the MOST likely reason the insecticide was less effective the second year?

Answer 1

Answer:

Worms that survived produced offspring that were resistant to the insecticide.