If you grimace in fear while taking a difficult exam, this facial expression is likely to cause you to experience increasingly intense feelings of fear. This best illustrates ___.

This best illustrates a sign of emotionality.

Explanation:

Facial expression is the term used to describe the movements we make with the face muscles that have the ability to act as a sign of emotionality, that is, facial expression conveys an emotional state that we are experiencing at the moment.

The emotionality we show through facial expression, usually gets stronger, as facial expression becomes intense and prominent. Being the main means of transmitting emission signals between humans.