Question

The fact that a sneer retains elements of baring one's teeth so as to threaten predators supports __________'s idea that in prehistoric times, before language, our ancestors communicated threats, greetings, and submission with facial expressions.

Answer 1

This supports Darwin’s idea. He speculated that earlier our prehistoric ancestors conversed in words, their capability to convey intimidations, greetings, and suggestion with facial languages assisted them to survive. That common inheritance, is why all creatures express the basic feelings with alike facial expressions.