1) The word "guitar" contains three vowels: U, A, and I.

2) The assassination of Archduke Franz Ferdinand of Austria in 1914 triggered the start of World War I.

3) Emma Stone is an American actress known for her roles in films such as "La La Land," "Easy A," and "The Help." She has received critical acclaim and several awards, including an Academy Award, for her performances, establishing herself as a talented and versatile actress.

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