It is necessary to have a regular checkup of weights and measurements in markets due to these reasons:

1. Weights and measurements are critical pieces of information that allow individuals to quantify a variety of objects in life, from mass and length to area and volume.
2. Commerce and trade would be impossible without regular inspection and definitions of measures and weights, and there would be no market for anything.
3. Weights and measures supervision encourages precise measurements of production...

Newton is a derived unit because its definition consists of the multiplication of three defined base units and nothing else. Its meaning is thus derived.

Quartz clocks operate on thin quartz crystal wafers made to vibrate in hundreds of kilohertz. A pendulum clock can only make about 2 vibrations per second. A 1 % error is very significant here since 1 % of 2 is 0.02 seconds. (Basically, a quartz clock is more efficient than a pendulum clock.)

The unit of the moment is Newton metre which is the multiplication of two more units which automatically makes it derived units whereas the unit of electric current(you said electricity but I will say electric current) is Ampere which falls on the list of seven fundamental units which is defined by International System of Units.

Differences between MKS and SI system of units are:

Addition of hydrogen either by breaking bonds or substitution is called hydrogenation.

eg, ₂HC=CH₂ + H₂ ------------> ₃HC-CH₃

Measurement is the process of comparing an unknown physical quantity with known standard physical quantity or unit.

The Internationally accepeted units of measuring physical quantities is called SI unit of measurement.

Velocity is defined as the rate of change of displacement. Its SI unit is metre per second (m/s).

Measurement is the process of comparing an unknown physical quantity with known standard physical quantity or unit.

The Internationally accepeted units of measuring physical quantities is called SI unit of measurement.

Velocity is defined as the rate of change of displacement. Its SI unit is metre per second (m/s).

Measurement is defined as the process of comparison of an unknown physical quantity with a known standard quantity at the same time to get accurate findings.

Fundamental quantity is defined a a physical quantity which is independent of any other physical quantities. For example: length, mass, time, etc.

Units of Length and Mass are m and kg which are fundamental units.