What is the more likely cause of directional selection?

Directional selection is often caused by changes in environmental conditions or the introduction of new selective pressures that favor a specific trait. For example, as climate changes or new predators emerge, individuals with advantageous traits that enhance survival and reproduction will become more common in the population. This process can lead to a shift in the overall phenotype of the population over time, favoring individuals that are better adapted to the new conditions.