Which plane geometry has countless symmetry axis ? (except for circle) Sorry if there are some grammatical mistakes in my question because English isn't my first language. Thank you very much !

Countless symmetry axis of a parabola is vertical line which divides the parabola into two congruent halves.

The axis of symmetry always passes through vertex of parabola. These will cause the plane to divide into two parts.

The geometric shape may have countless symmetry axis. This actually divides the shape into two halves and creates a mirror like effect.

The x-coordinate of vertex is equation of axis symmetry of parabola. Lets say if we take an example of quadratic equation which is ,

y = ax^2 + bx + c , here in this equation the axis of symmetry is vertical line which is x = - b^2 a

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