The fundamental unit in S.I system are

The seven SI base units are the fundamental building blocks of measurement, defining core physical quantities: the meter (m) for length, kilogram (kg) for mass, second (s) for time, ampere (A) for electric current, kelvin (K) for temperature, mole (mol) for amount of substance, and candela (cd) for luminous intensity, all established with modern definitions tied to universal physical constants.