A drawing sheet changes when you draw a picture on it. Can you reverse this change?

Hint: Changes can be of two types reversible change and irreversible change. Reversible changes are those that can be exactly reversed such that the state before and after the change is exactly the same.

Complete step by step answer:
Now let’s understand what irreversible changes are; these are the changes that cannot be reversed. These changes are permanent in nature and the state before the change can never be achieved again. The situation given in the question states that a picture is drawn on the drawing sheet. The process of drawing the picture determines whether the change will be reversible or irreversible. The cases arising in the situation could be the following:
 We can reverse the change of the picture drawn if it is made by pencil on the drawing sheet by using an eraser but even if the picture is erased one might not get the drawing sheet in the state before drawing the picture on it as it may get withered. Since the drawing which was written by using a soft pencil can be erased by using an eraser it can be reversed with-out damaging the drawing sheet entirely and it can be reused to draw it is a reversible change in this case.
We can’t reverse this change if the picture is made by a pen, oil color, or sketch pen as it is difficult to erase them and it is not easy to erase the drawing which was drawn using pen, oil paints, color or sketch pen. Pictures drawn using such methods can not be erased therefore it is an irreversible change in this case.

Note:
We can therefore conclude that the process of drawing a picture on the sheet could be reversible or irreversible depending upon the way the picture is drawn.