1. Sunspots: These are cooler, darker areas on the Sun's photosphere (surface). They appear darker because they are slightly cooler than the surrounding photosphere. Sunspots are caused by intense magnetic activity that inhibits the flow of hot plasma from the Sun's interior.

2. Solar Flares: These are sudden, intense bursts of energy released from the Sun's atmosphere, often associated with sunspots. They can release enormous amounts of radiation and energy into space, which can affect Earth's atmosphere and even disrupt communication systems.