There are 6 layers in the sun, from the inside to the out. There is the core, the radiation zone, the convection zone, the photosphere (the surface of the sun), and the chromosphere and the corona (2 layers of gas).
Sunspots are dark spots that take place on the photosphere. They are spots that occur on the sun every 11 years. Sunspots have 2 parts. They are the umbra and the penumbra. The umbra is on the inside and is very dark, but the penumbra is on the outside and is not as dark. Sunspots can grow up to over 50 thousand kilometers wide.