1) The hibiscus flower is commonly associated with tropical regions and is the national flower of several countries, including Malaysia, South Korea, and Haiti.

2) The word "school" contains two vowels: O and O.

3) The Pacific Ocean is the largest ocean on Earth, covering more than 30% of the planet's surface.

4) The NBA (National Basketball Association) is widely regarded as one of the most popular and competitive professional basketball leagues in the world.