Question

mineralized veins containing valuable metals were deposited by ______.
volcanic ash
erosion
hydrothermal fluids
fast - flowing liquid lava

Explanation:

Hydrothermal fluids are known to deposit mineral - ized veins with valuable metals. They carry dissolved minerals and metals and can deposit them in cracks and fissures to form veins. Volcanic ash is mainly fine - grained particles from volcanic eruptions and not a main source for depositing such veins. Erosion is the process of wearing away of earth materials and not a depositional agent for valuable metal - bearing veins. Fast - flowing liquid lava is molten rock and does not typically deposit mineralized veins of valuable metals in the same way as hydrothermal fluids.

Answer:

C. hydrothermal fluids