A line on any plane figure which would divide the figure into two equal parts.
These parts when folded over should coincide with one another.
It is an imaginary line that produces a mirror image of a shape which is its line of symmetry
There is no such thing. An axis (plural = axes) of symmetry (not symmerty) for any plane figure is a line which divides the figure into two shapes that are mirror images of one another.
180 degrees
1
4
Yes
Three
Order 4.
It would help if you checked your spelling before posting the question. I can guess that "symmerty" is meant to be symmetry but I have no idea what a hepaton is. Sorry.
No. But it does have rotational symmetry of order 2.
bilaterally symmetry
Yes, of order 2.