Natural selection is the main mechanism that determines which traits will be passed on to the next generation in greatest frequency. Natural selection is the process by which organisms that are better adapted to their environment are more likely to survive and reproduce. This means that the traits that help organisms survive and reproduce are more likely to be passed on to the next generation.

There are a number of factors that can influence natural selection, including:

* The environment: The environment can change over time, which can change which traits are beneficial. For example, a climate change could make it more beneficial for animals to have thicker fur or to be able to migrate to a warmer climate.

* The population: The population of organisms can also influence natural selection. For example, if there are a lot of organisms that are competing for resources, then the traits that help organisms compete for resources are more likely to be selected for.

* The species: The species of organism can also influence natural selection. For example, some species of animals may be more likely to be preyed upon than other species, which can lead to the selection of traits that help animals avoid predators.

Natural selection is a powerful force that has shaped the evolution of life on Earth. It is responsible for the diversity of life that we see today, and it will continue to shape the evolution of life in the future.