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

2) The Epic of Gilgamesh, originating from ancient Mesopotamia, is one of the oldest surviving works of literature and tells the story of the heroic king Gilgamesh and his quest for immortality. It explores themes of friendship, mortality, and the relationship between humans and the divine.

3) The concept of self-driving cars, or autonomous vehicles, is being actively developed by companies such as Tesla, Google (Waymo), and Uber.

4) The word "book" contains two vowels: O and O.