Final answer:
An explosive volcanic mudflow containing ash, rock, and water is true. This type of mudflow is called a lahar and can be very destructive.
Step-by-step explanation:
Explosive volcanic mudflow containing ash, rock, and water is true. This type of mudflow is called a lahar. Lahars are formed when volcanic material, such as ash and rock, mixes with water, either from heavy rainfall or the melting of ice and snow on the volcano. The combination of water and volcanic material creates a fast-moving flow that can be destructive and carry debris over long distances.