Question

multiple - choice question
——— is silt, mud, and goop in rivers.
sediment
rocks
metals

Explanation:

Silt, mud, and goop in rivers are types of sediment. Sediment is loose - material like sand, clay, and silt that is transported and deposited by water, wind, or ice. Rocks are solid and more massive than sediment, and metals are chemical elements with specific physical and chemical properties, which are not what silt, mud, and goop are primarily categorized as.

Answer:

Sediment