The answer is language. Humans have a high degree of language acquisition and complexity compared to
chimpanzees due to foxp2 proteins. Foxp2
are transcription factors that are significant in cell proliferation. The difference of 2 in 700 amino acids in the sequence makes the protein to be differentially regulated between the two
species.
The right answer is language (speech, talking, or every thing related to communication skills).
Forkhead-Box P2 protein (FOXP2) is a transcription factor belonging to the Forkhead-Box3,4 protein group. it is recognized that FOXP2 plays a large role in language transmission, including grammatical abilities.
The name "speech gene" has been popularized for the FOXP2 gene. But many other vertebrates also have this gene, and FOXP2 seems to play a role in verbal communication.