Answer
During the first treatment of the insecticide which are sensitive to it will die. But other who have slight resistance will survive. This resistance will carried to next generation, and insects will develop greater resistance to the insecticide.
Work Step by Step
During the first treatment of the insecticide which are sensitive to it will die. But other who have slight resistance will survive. This resistance will carried to next generation, and insects will develop greater resistance to the insecticide.