Read Chapters 16 from Discovering Astronomy.
WebAssign -- Chapter 16. Answer homework questions covering Chapter 16.
The latest mission to study Sun is SOHO (Solar & Heliospheric Observatory), a joint mission of the European Space Agency (ESA) and NASA. It was launched in December, 1995, and continues to study Sun and send back data to this day.
Picture taken by SOHO in 1997.
In this chapter, you should know the layers of Sun's atmosphere and some of the features seen on Sun.