Why can we say that charge of any body is always an integral multiple of e ?

Explanation

If the protons and electrons are the only basic charges in the universe, all the observable charges have to be integral multiples of e.
If a body containss `n_(1)` electrons and `n_2` protons, the total amount of charge on the body is `n_(2)e + n_(1)(-e) = (n_(2) - n_(1))e`
where `n_(1)` and `n_2` is integral multiples. and their difference = `n_(2)e - n_(1) (-e)`
`=(n_(2) + n_(1))e` also an integer.
Thus, the charge on any body is always an integral multiple of e and can be increased or decreased also in steps of e.