Probably (Who is the main character of the story?) because exposition " introduces the characters, describes the setting and establishes the problem in the story." Is this helpful?
I'd say the
size of the frame.
The size, quantity and color combination of pixels is
measured in terms of display resolution. A resolution, however, is the number
of pixels in an image and is identified by the width and the height. How you’ve
set the resolution for the display screen will determine the specific size of
the pixels.