Question

question 18
a protolith:
○ is always metamorphic rock.
○ is always igneous rock.
○ may be any of the three rock types.
○ is always sedimentary rock.

Explanation:

A protolith is the original rock before it undergoes metamorphism. It can be any of the three main rock - types: igneous, sedimentary, or metamorphic. For example, a sedimentary rock like shale can become a metamorphic rock like slate through metamorphism, with shale being the protolith. Similarly, an igneous rock or another metamorphic rock can also be a protolith for further metamorphic changes.

Answer:

C. may be any of the three rock types.