You are reading a scientific paper regarding the relationships of the anatomical and behavioral characteristics of chimpanzees and their implications for early hominid evolution. You note that the authors refer to human ancestors as hominids. This implies that the researchers are relying on _________.

The family Hominidae of order Primates incorporates chimpanzees and humans. Proof from the fossil record and from a correlation of human and chimpanzee DNA proposes that humans and chimpanzees wandered from a typical hominoid progenitor roughly 6 million years back. A few animal types developed from the transformative branch that incorporates humans, in spite of the fact that our species is the main enduring part.
The term hominin (or primate) is utilized to allude to those species that developed after this split of the primate line, along these lines assigning species that are more firmly identified with humans than to chimpanzees. Hominins, who were bipedal in contrast with different hominoids who were fundamentally quadrupedal, incorporates those gatherings that most likely offered ascend to our species: Australopithecus africanus, Homo habilis, and Homo erectus, alongside non-familial groups
Hence, the answer is "researchers are relying on classification of human and chimpanzees"