Please choose the correct answer to the question: A farmer sprayed his orange trees with a pesticide to eliminate the insects damaging the trees. Some of the insects survived and produced offspring that were also resistant to the insecticide. Which process is illustrated by the pesticide resistance of the offspring?

Answer1: natural selection Answer2: selective breeding Answer3: aerobic respiration Answer4: sexual reproduction

Answer format: answer1/answer2/answer3/answer4
Answer: answer1