How does natural selection affect the evolution of species?

• A. By enhancing genetic drift
• B. By favoring individuals with advantageous traits
• C. By decreasing genetic variation
• D. By preserving all traits equally

Answer: (B)

Natural selection is a fundamental mechanism of evolution, operating by favoring individuals that possess advantageous traits that enhance their survival and reproductive success in a given environment. This process leads to the gradual adaptation of populations over generations. Individuals with traits that are better suited for their environment tend to reproduce more successfully than those without such traits, resulting in those advantageous traits becoming more common in the population over time.

For example, if a particular environment favors faster individuals in a species of prey, those individuals are more likely to escape predators, survive, and reproduce, passing on the genes associated with their speed to the next generation. Over time, the gene pool of that species shifts toward the traits that confer advantages, illustrating the mechanism of natural selection.

In contrast, other options do not accurately capture the primary role of natural selection. While genetic drift and changes in genetic variation can occur, they are not directly influenced by natural selection in the same way. Genetic drift is a random process that can lead to changes in allele frequencies regardless of the traits' effects on survival and reproduction. Similarly, preserving all traits equally runs counter to the very premise of natural selection, which is inherently about differential survival and reproduction based on trait advantages. Thus, favoring individuals with advantageous traits is indeed the cornerstone