What are Units and It's type?

What is Unit? Unit is the quantity of a constant magnitude which is used to measure the magnitudes of other quantities of the same nature. For the measurement of a physical quantity a definite magnitude of quantity is taken as standard and the name given to this standard is called unit. Properties of Unit (a) The unit should be well-defined. (b) The unit should be of some suitable size. (c) The unit should be easily reproducible. (d) The unit should not change with time. (e) The unit should not ...