Here's why:

* Environment: The environment includes all the factors that influence an organism's survival, like climate, food availability, predators, and competition.

* Survival and Reproduction: Organisms with traits that make them better suited to their environment are more likely to survive, reproduce, and pass those traits on to their offspring.

* Evolution: Over time, the frequency of advantageous traits increases in a population, leading to evolution.

Let me know if you have any other questions about biology or natural selection!