1) The word "book" contains two vowels: O and O.

2) The United States operates under a two-party system, with the Democratic Party and the Republican Party being the two major political parties that compete in elections and shape the country's political landscape.

3) The Victoria Amazonica water lily has leaves that can grow up to 10 feet (3 meters) in diameter, making it one of the largest aquatic plants.

4) The universe is estimated to be around 13.8 billion years old.