Final answer:
The single common principle that operates across biology, behavior, and culture is natural selection. It drives evolutionary change by favoring traits that enhance survival and reproduction, influencing genetics, behaviors, and cultural developments over time.
Step-by-step explanation:
The single common principle operating at the level of biology, behavior, and culture is natural selection. Natural selection is a major mechanism of evolution as described in biological principles. It operates by giving reproductive success to individuals with traits that are better suited to their environments, and as a result, these traits become more common in the population over generations. This process can lead to adaptations that enhance an organism's ability to survive and reproduce. Natural selection affects the biological aspect through genetic changes, influences behavior through the success of behaviors leading to better survival and reproduction, and impacts culture through cumulative changes over time that can be seen, for example, in the progression of tools and technologies.