Final answer:
Chimpanzees are the great ape species that is most closely related to humans.
Step-by-step explanation:
The great ape species that is most closely related to humans is the chimpanzee. Chimpanzees are considered to be our closest living relatives in the primate order. Genetic evidence suggests that human and chimpanzee lineages diverged from a common ancestor about 5 to 7 million years ago.