which of the following statements is true of a reflection?
-it is an isometry.
-it slides a plane.
-the transformation is done over a line of reflection.
-it flips a plane about a fixed line.
i-t changes the size of the figure being reflected.

I think the correct answers from the choices listed above are the first and the fourth option. The statements that are true about a reflection would be that it  is an isometry and the it flips a plane about a fixed line. A reflection over a line k (notation rk) is a transformation in which each point of the original figure (pre-image) has an image that is the same distance from line k.