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

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

3) The word "mountain" contains three vowels: O, U, and A.

4) Cristiano Ronaldo is a Portuguese professional soccer player widely regarded as one of the greatest footballers of all time. He has won numerous awards, including multiple FIFA Ballon d'Or titles, and has played for top clubs such as Manchester United, Real Madrid, and Juventus.