How does natural selection influence human evolution?

Natural selection is a key mechanism of evolution that leads to changes in the genetic makeup of populations over time. It operates on the principle that individuals with traits that are better suited to their environments are more likely to survive and reproduce. This means those advantageous traits become more common in the population.

In the context of human evolution, natural selection has influenced various traits like skin color, lactose tolerance, and even disease resistance. For instance, in regions with high UV radiation, individuals with darker skin may have a survival advantage because their skin offers protection against sun damage, leading to a higher rate of survival and reproduction compared to those with lighter skin. Over generations, this can shift the population's genetic makeup towards traits that are more beneficial in that environment.

The other options do not accurately reflect the process of natural selection. It doesn't promote the survival of the weakest individuals, nor does it guarantee equal success for all traits, as some traits provide a survival advantage while others may not. Furthermore, natural selection is not confined to stable environments; it can also occur in changing conditions, which can drive rapid evolutionary changes.