Here's why:

* Medium size: The Sun is classified as a G-type star, which falls in the middle of the size range for stars. It's neither a giant nor a dwarf.

* Yellow: The Sun appears yellow to us due to the way its light interacts with the Earth's atmosphere.

* Mostly hydrogen and helium: Stars are giant balls of hot gas, and the Sun is primarily composed of hydrogen (about 70%) and helium (about 28%). These elements fuse together in the Sun's core, releasing energy in the form of light and heat.