ELI5 How can we know Homo sapiens are the only ones left?
I just read about the link between Dragon Man and Denisovans. How do we know Homo sapiens are the only subspecies to exist? People are so vastly different from the short and stocky Aztec and Mayan to the incredibly tall and lanky South Sudanese. How do we know we aren’t all different subspecies? I understand evolutionary biology and why we all look different, but I don’t understand why we believe no other sub species exists.