assistant: Second (s) - The unit of time is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.

Metre (m) - The unit of length is defined as the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second.

Kilogram (kg) - The unit of mass is defined as the mass of the International Prototype of the Kilogram, a platinum-iridium cylinder kept at the International Bureau of Weights and Measures in France.

Ampere (A) - The unit of electric current is defined as that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed one meter apart in vacuum, would produce between these conductors a force equal to 2 x 10^-7 newtons per meter of length.

Kelvin (K) - The unit of thermodynamic temperature is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water.

Mole (mol) - The unit of amount of substance is defined as the amount of substance that contains as many elementary entities as there are atoms in 0.012 kilograms of carbon-12.

Candela (cd) - The unit of luminous intensity is defined as the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 10^12 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.

assistant: Yes, of course! Seven base units that serve as the framework for all other units in the International System of Units (SI) are defined. The descriptions of each of the seven base units are as follows:

The meter (m), the fundamental unit of measurement, is the distance covered by light in vacuum over a period of time equal to 1/299,792,458 seconds.

The kilogram (kg), the fundamental unit of mass, is the weight of the platinum-iridium cylinder known as the International Prototype of the Kilogram, which is held at the International Bureau of Weights and Measures (BIPM) in France.

The definition of a second (s), the fundamental unit of time, is the length of a radiation cycle (9,192,631,770 cycles), which corresponds to the change from one energy level of the cesium-133 atom to another.

Ampere (A): The ampere is the fundamental unit of electrical current and is defined as the constant current that, if maintained in two parallel, straight conductors of infinite length and negligible circular cross-section, spaced one meter apart in vacuum, would result in a force between these conductors of 2 x 10-7 newtons per meter of length.

The base unit of thermodynamic temperature is the kelvin (K), which is equal to 1/273.16 of the triple point of water's thermodynamic temperature. (0.01 degrees Celsius).

The mole, abbreviated as mol, is the basic unit of substance quantity and is defined as the quantity of a substance containing as many atoms, molecules, or ions as there are in 0.012 kilograms of carbon-12.

Candela (cd): The candela is the basic unit of luminous intensity and is defined as the amount of light emitted in a particular direction by a source having a radiant intensity of 1/683 watt per steradian and emitting monochromatic radiation with a frequency of 540 x 1012 hertz.

The foundation of the SI system is made up of these seven base units and their corresponding definitions, which serve as the cornerstones for all other units of measurement.