Which process describes how traits become more common in a population over generations?

• A. Genetic drift
• B. Natural selection
• C. Mutation
• D. Gene flow

Answer: (B)

The process through which traits become more common in a population over generations is known as natural selection. This mechanism operates on the principle that individuals with certain advantageous traits are more likely to survive and reproduce in a given environment. As these individuals pass on their genes to the next generation, the traits that provided a survival advantage increase in frequency within the population.

Natural selection can occur due to environmental pressures, such as changes in food availability, the presence of predators, or climatic shifts. Over time, this leads to a gradual adaptation of the population to its environment. It is important to recognize that natural selection is a key driving force behind evolution, as it shapes the genetic makeup of populations based on the reproductive success of individuals.

In contrast, genetic drift refers to random changes in allele frequencies, especially in small populations, and does not require specific advantages of traits. Mutation introduces new genetic variations into a population but does not inherently increase the prevalence of traits unless they confer a benefit. Gene flow involves the transfer of alleles from one population to another, which can introduce new traits but is distinct from the selective process that increases trait prevalence based solely on fitness advantages in a given environment.