Final answer:
The culture dating back to 2.5 million years ago includes the use of stone tools by early humans, marking the beginning of the Paleolithic Age and representing an early form of human culture.
Step-by-step explanation:
The piece of culture that dates back to 2.5 million years ago is the use of stone tools. Humankind's earliest ancestors began using these for a variety of purposes, marking the start of the Paleolithic Age. Tools like hammerstones were among the first to appear in the archaeological record, with more advanced tools such as ax points for hunting appearing around 1.75 million years ago. This innovation spread widely as prehistoric groups migrated and interacted. Moreover, the earliest known artwork, such as the figurative cave paintings in Indonesia and Borneo, suggests that early humans had developed the cognitive capacity for creating pictorial images well before the rise of advanced civilization in regions like Mesopotamia and Ancient Egypt.