Final answer:
The statement is true. Pyroclastic flows consist of hot gas and volcanic matter that travel rapidly and are extremely hazardous, capable of destroying everything in their path and causing fatalities.
Step-by-step explanation:
The statement that pyroclastic material travels rapidly down a volcano and is a hazard is true. Pyroclastic flows are fast-moving currents of hot gas and volcanic matter (collectively known as tephra) that move away from a volcano at speeds typically as fast as 700 km/h (450 mph).
For instance, during the eruption of Mount Vesuvius, pyroclastic material traveled down to the nearby cities of Pompeii and Herculaneum, leading to the preservation of organic materials, human remains, and non-organic artifacts such as frescoes and mosaics. Such flows are considered extremely dangerous due to their speed, high temperature, and the ability to suffocate and incinerate anything in their path.