Why can’t we use the units of measurement used on earth?

The irrevocable utility of the units comes from the scientific world, but also from the economic and commercial world, which require a simple and fixed reference for their correct functioning.

But we see in history, that the units have multiplied and the will for universality and simplicity have rarely been a reality since the divergences of interest helping, the measurements were for a long time related to a multitude of standards, different according to the place, the time and the nature of the product, the reference often having a complex definition, the standard was difficult to reproduce and therefore the measurements not very precise, which unfortunately led to misunderstandings and inconsistencies.

A unit of measurement is defined by a standard, the standards must have the following qualities:

- maximum precision (determining factor because the standard can therefore change if technology evolves and finds a more precise one)

- natural and invariant character (in time and space)

- reproducible

remark: the defining relations are arbitrary, and the universality of the standard can only result from a convention between men.

the answer is d.) potassium