No
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.
The letter "Z" has two lines of rotational symmetry. When rotated 180 degrees, it looks the same, but it does not have any other angles at which it maintains its appearance. Thus, it exhibits rotational symmetry only at this specific angle.
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.