__ 14. Humans have promoted the evolution of insects that are resistant to insecticides by a. trying to control pests with chemicals. b. using insecticides that are outdated. c. using the wrong insecticide. d. breeding more useful insects.

## Step 1<br />This problem is about understanding the concept of natural selection and its application in the context of insecticide resistance. The question is asking us to identify the human activity that has led to the evolution of insects that are resistant to insecticides.<br /><br />## Step 2<br />The principle of natural selection states that organisms that are better adapted to their environment are more likely to survive and reproduce. In this case, insects that are resistant to insecticides are more likely to survive and reproduce because they are not killed by the insecticides.<br /><br />## Step 3<br />Over time, the frequency of these resistant insects increases in the population, leading to a population of insects that are largely resistant to the insecticide. This is because the insects that are not resistant are killed by the insecticide, leaving the resistant insects to survive and reproduce.<br /><br />## Step 4<br />Looking at the options provided, option A, "trying to control pests with chemicals", is the activity that has led to the evolution of insecticide-resistant insects. This is because the use of chemicals (insecticides) to control pests creates an environment where insects that are resistant to these chemicals have a survival advantage.