Final answer:
The evidence of behavioral modernity and an ancient diet at the Pinnacle Point cave site in South Africa is significant because it shows that early humans were behaviorally modern and provides insights into their diet and daily life.
Step-by-step explanation:
The significance of the evidence of behavioral modernity dating back to 164,000 B.P. at the Pinnacle Point cave site in South Africa is that it indicates that Homo sapiens in the Middle Stone Age possessed the capacity for modern symbolic thought. This means that they were not only anatomically modern, but also behaviorally modern. The evidence of an ancient diet containing a variety of shellfish and marine sources is important because it helps anthropologists understand the diet and food practices of early humans, as well as their daily life, division of labor, cultural traditions, and health.