Why does the resistance of insect pests to pesticides increase over time?

1) In the population of insect pests due to the appearance of mutations, individuals resistant to pesticides appear over time.
2) These individuals are preserved by natural selection and their number in subsequent generations increases.
3) Therefore, previous doses or types of pesticides already cease to act on pests.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.