Final answer:
Mt. Lassen is an example of a plug dome volcano, which is characterized by viscous lava that forms a steep-sided dome, with sulfur deposits often found in such volcanic areas.
Step-by-step explanation:
Mt. Lassen, which erupted in 1915, is an example of a plug dome volcano. This type of volcano is characterized by viscous lava that cools and piles over the vent, often forming a steep-sided dome.
The presence of sulfur deposits is common in volcanic areas, as sulfur gases are released from the magma. Similar to other volcanic eruptions, such as the explosive eruption of Mt. St. Helens in 1980, Lassen's eruption showcased the dramatic and transformative power of Earth's geologic processes.