Natural selection is an evolutionary mechanism by which
a. advantageous traits are eliminated in a population
b. advantageous traits become more common in a population
c. inherited traits pass consistently through generations
d. organisms choose which traits to look for in their offspring

The correct answer for the fill in the blank is B) Advantageous traits become more common in a population.

Theory of natural selection was given by Darwin. This is one of the mechanisms of evolution.

According to this theory, organisms that are better adapted to their environmental conditions survive and increase their population by reproduction. So they pass the advantageous trait to the next generation. In other words, it reflects the survival of the fittest.

Due to this, the advantageous trait becomes more common in the population.

Thus, the correct option is B)