The letter z is one which has no lines of symmetry so the answer is 0.
No.
1
Depending on the font, they are N, S and Z.
yes, but only two....
z
Z
The letter "O" has rotational symmetry, as it looks the same when rotated 180 degrees.
With a very apologetic face because it is not true.
One, if you draw a line from the top left of the Letter Z to the bottom right, then it is a mirror image on either side.
ALL letters have at least one line of rotational symmetry. However - if you mean reflective symmetry, the letters F, G, J, L, P, Q, R, S, & Z do not.
It has rotational symmetry.