1) Mountains are important water sources, as they capture and store precipitation, feeding rivers and supporting ecosystems downstream.

2) The word "elephant" contains three vowels: E, A, and E.

3) The world's largest desert is the Sahara Desert in Africa, covering an area of about 3.6 million square miles (9.4 million square kilometers).

4) The development of the World Wide Web Consortium (W3C) and web standards has ensured interoperability and compatibility across different web browsers and devices.