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

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

3) The name "Bluetooth" comes from the 10th-century Danish king, Harald Bluetooth, who united Denmark and Norway.

4) Robert Downey Jr. is an American actor known for his portrayal of Iron Man in the Marvel Cinematic Universe. He has also starred in films such as "Sherlock Holmes," "Chaplin," and "Tropic Thunder," and has received critical acclaim and commercial success for his performances.