1) The process of nuclear fusion powers the sun and other stars, fusing hydrogen atoms together to form helium and releasing vast amounts of energy in the process.

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

3) In Norse mythology, the World Tree, known as Yggdrasil, is a massive ash tree that connects the nine realms of existence. It is considered the center of the cosmos and serves as a conduit between different realms, including Asgard (realm of the gods), Midgard (realm of humans), and Helheim (realm of the dead).

4) The concept of banking dates back thousands of years, with evidence of early banking activities found in ancient civilizations such as Mesopotamia and Egypt.