What are sunspots and how are they related to the Sun's magnetic field? Is the magnetic field stronger weaker in sunspots?

What are sunspots and how are they related to the Sun’s magnetic field? Is the magnetic field stronger weaker in sunspots? How does the temperature in a sunspot relate to the temperature in the rest of the photosphere? Describe the role of the Sun’s differential rotation in the formation of sunspots. Describe (briefly) the 22 year solar cycle, stating its essential features.