There's no single system used for all scientific measurements. However, the most widely used and internationally recognized system is the International System of Units (SI).

Here's why:

* Standardization: SI provides a universal language for scientists across the globe, facilitating communication and collaboration.

* Consistency: The system uses a coherent set of base units and derived units, ensuring consistency and accuracy in scientific research.

* Decimal System: SI relies on the decimal system, making calculations and conversions easier.

While SI is the dominant system, other systems are still used in specific fields:

* Imperial System: Still used in the United States and some other countries, especially in everyday life.

* CGS system: Used primarily in specific areas of physics.

It's important to remember that even within the SI system, different fields might utilize specific units for convenience or historical reasons.