Infinitely many.
a heart have no rotational symmetry!
A regular hexagon has 6 rotational symmetries (rotational symmetry of order six) and 6 reflective symmetries (six lines of symmetry).
A kite has only one line of rotational symmetry, as it is only the same if it is tilted once. (back to its normal position).
a circle or a sphere
Rotational symmetry of order 1.
It has 8 rotational symmetry.
An ellipse has rotational symmetry of order 2.
2
yes, in fact it can have 6 rotational symmetries.
5
9 reflection
18
Two.
a heart have no rotational symmetry!
A regular hexagon has 6 rotational symmetries (rotational symmetry of order six) and 6 reflective symmetries (six lines of symmetry).
A seven-pointed star has seven rotational symmetries. This means it can be rotated in increments of ( \frac{360^\circ}{7} ) and still appear unchanged. Each of these rotations corresponds to one of the seven points of the star. Therefore, the total number of rotational symmetries is equal to the number of points.
no rotational symmetry