Lines of symmetry, I think is what you meant to write, is... well it's easier this way:
Think of any shape: in this example we'll use a square. ONE of its lines of symmetry is right down the middle, because then both sides are the same. So, a line of symmetry is a line that divides a shape into to exactly the same shapes (except they are facing the other way.)
N has no lines of symmerty !
4
1
4
zero
one
A sphere.
5.
Yes
It varies depending on the angles and lines of the triangle.
An equilateral triangle has 3 lines of symmetry
Three axes of symmetry.