Hello, i am the Metric System, or commonly known as the International System of Units. All of my units have a single quantity of measurement in base 10 almost globally, and responsible for Celsius (°C), which uses boiling and freezing point of water as reference points (0°C is freezing point of water, and 100°C is the boiling point of water), and Kelvin (K, doesn't use degrees) which is defined as 'absolute zero' (-273.15°C) and serves a purpose of thermodynamic temperature. If you have any questions, please don't hesitate to ask!