In geological terms, what does the presence of a xenolith suggest about the history of the surrounding rocks?

The presence of a xenolith provides significant insight into the geological history of the surrounding rocks. Xenoliths are fragments of rock that differ from the main body of rock in which they are found, typically embedded in an igneous rock. Their presence often indicates that the surrounding rocks have undergone volcanic activity. This is because xenoliths are usually brought to the surface by magma, which can incorporate and transport pieces of rock from the Earth's crust as it rises. When volcanic activity occurs, these xenoliths can be preserved in the cooling magma or lava that forms igneous rock.

Recognizing that xenoliths are frequently indicative of previous geological processes associated with volcanic activity helps geologists understand the interactions between different rock types and the history of the magma that generated the igneous body. Thus, the correct answer reflects an important aspect of interpreting the geologic history tied to magma movement and the resulting rock formation processes.