What does the term evolution refer to in biology?

In biology, evolution refers to the history and development of a species or race, including the changes and variations that occur over time. This concept encompasses the process through which species adapt to their environments, undergo changes in genetic composition, and ultimately give rise to new species.

The understanding of evolution emphasizes the gradual changes that occur within populations due to genetic variation, selection pressures, and the time scale over which these changes accumulate. This historical perspective allows scientists to trace the lineage of organisms and understand their adaptations to various ecological niches.

Other options listed, while related to the concept of evolution, do not encapsulate the broader definition as effectively. Natural selection is one of several mechanisms that drive evolutionary change, genetic drift represents random changes in allele frequencies that can occur independently of selection, and environmental adaptation describes the adjustments organisms make to their surroundings but does not fully address the historical aspect of evolution. Thus, option B is the most comprehensive and accurate reflection of what evolution means in the context of biology.