Shading is showing the objects' roundness or shape; shade is the blocking of a light source; and shadow is the variation between black and white with the darkest part at the center and the 'shadow' fades at the edges.
Yes.............................
It's a condition in which people see white or black dots in parts or the whole of their visual fields.
Cave paintings are evidence of artistic ideas, language, and (possibly) religious ideas as well.
