Final answer:
The most prominent similarity between Homo erectus and modern humans is their ability to adapt to changing climates and environments
Step-by-step explanation:
The most prominent similarity between Homo erectus and modern humans is their ability to adapt to changing climates and environments. Both species relied on fire for warmth and cooking, made and used sophisticated stone tools, and worked cooperatively with each other to hunt and forage. Additionally, Homo erectus showed evidence of caring for the sick and elderly, indicating a level of compassion and social cooperation that is also observed in modern humans.