1) 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.

2) The world's largest volcano, Mauna Loa in Hawaii, is also one of the most active. It stands over 13,000 feet (4,000 meters) above sea level.

3) The word "piano" contains three vowels: I, A, and O.

4) The Atlantic Ocean is the second-largest ocean and is known for its strong ocean currents, including the Gulf Stream.