According to the theory of evolution, traits will become common in a population over time. recessive female male favorable

According to the theory of evolution, _favorable_ traits will become common in a population over time.
"Favorable," that is in a survival sense. Remember, all that matters [to the genes] is for the individual to function and survive long enough to reproduce, and thus continue those genes into a new generation, the offspring. Natural selection finds certain adaptations "favorable" if they aid in the individual's ability to survive long enough to reproduce. Evolution, on the other hand, looks at a population and how over time these favorable genes change the individuals' genetic makeup within that population.