What process allows a species to better adapt and reproduce over generations?

The process that allows a species to better adapt and reproduce over generations is adaptation. Adaptation refers to the changes in physical characteristics or behaviors that enhance a species' ability to survive and thrive in its environment. These changes often occur as a result of natural selection, where individuals that possess traits better suited to their environment are more likely to survive, reproduce, and pass on those advantageous traits to their offspring.

This process is ongoing, allowing the species to become well-adjusted to their habitat over many generations. Adaptation can involve structural changes, such as the development of thicker fur in colder climates, or behavioral changes, such as migration patterns that align with resource availability.

The other options relate to aspects of genetics and population dynamics but do not embody the entire process of adapting over generations. DNA is the hereditary material governing traits, genetic drift refers to random changes in gene frequency in a population, and mutations introduce new genetic variations but require the process of natural selection to lead to adaptation. Therefore, adaptation encapsulates the full cycle of evolutionary change that improves survival and reproduction in a species.