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

2) The sunflower is not a single flower but a cluster of small flowers arranged in a spiral pattern.

3) The word "banana" contains three vowels: A, A, and A.

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