Final answer:
The temperature closest to zero is 0K, or absolute zero. Absolute zero is the lowest possible temperature at which all molecular motion ceases.
Step-by-step explanation:
The temperature closest to zero is 0K, or absolute zero. Absolute zero is the lowest possible temperature that can be theoretically achieved, corresponding to -273.15°C. It is the point at which all molecular motion ceases.
Kelvin (K) is an absolute temperature scale in which 0K represents absolute zero. It is the temperature scale most often used in astronomy and is measured from the lowest possible temperature.