1) The ocean covers about 71% of the Earth's surface and contains roughly 97% of the planet's water.

2) Serena Williams is an American professional tennis player widely regarded as one of the greatest athletes in the sport. She has won numerous Grand Slam titles and Olympic gold medals and has become an influential figure both on and off the tennis court.

3) The Federal Reserve System, often referred to as the Fed, is the central banking system of the United States.

4) The English alphabet has five vowels: A, E, I, O, and U.