What is a fermata and how does it work?

Explanation:

Adding on the previous answer, yes, fermata is when a note is held longer than the sheet music says.

It may not necessarily be in singing, but also any instrument, whether it can "hold" a sound or not. For example, a guitar string may no longer ring, but the note is technically "held".

Usually, you look at the conductor to gesture how long to hold the note until muting.

It looks like Ω with a dot in the centre.

A visual artist is simply someone who is using the visual methods (painting, sculpture, photography, so not methods that include  auditory aspects and also not through text such as literary artists do) to convey a message - so the best answer is :
a. captures the meaning and importance of a subject through visual representation instead of words.