1) The coldest known temperature in the universe was achieved in a laboratory in 2019, reaching a fraction of a degree above absolute zero (-273.15 degrees Celsius).

2) The concept of sovereignty refers to the supreme authority and power of a state to govern itself, make decisions, and control its own territory without interference from external forces.

3) The Dow Jones Industrial Average (DJIA) is a stock market index that tracks the performance of 30 large, publicly owned companies in the United States.

4) The Arctic Ocean is the smallest and shallowest ocean, located at the North Pole. It is covered by sea ice for much of the year.