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

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

3) The concept of gravity was famously described by Sir Isaac Newton after an apple fell on his head.

4) The world's largest volcano, Mauna Loa in Hawaii, is also one of the most active.