Final answer:
The species closest to humans in terms of violence and use of tools is the chimpanzee.
Step-by-step explanation:
The species that is closest to humans in terms of violence and use of tools is the chimpanzee. Chimpanzees are known to exhibit violent behaviors, especially during territorial disputes or when competing for resources. They have been observed engaging in aggressive encounters, including fighting and hunting cooperatively in groups. In addition to their violent tendencies, chimpanzees also use tools in various ways. They use sticks and rocks as weapons, as well as tools for cracking nuts, extracting termites from mounds, and fishing for termites using specially crafted tools.