Question

A whole can be just one unit or a group of object taken as one unit means

Answer 1

The whole means, the entire group, like all the fingers on our hand make up a whole set of fingers. It can also mean a group of objects, like a collection of 8 color pencils can be a whole pencil box.

A whole can also be just a unit. For example, ruler or scale that is used to measure the length of an object. But, we can divide the ruler into various parts, say, 30 centimeters, ie 30 equal divisions and, each division is called a centimeter.