Gneiss is a metamorphic rock formed from?
The correct answer is: A
Explanation
Gneiss is a metamorphic rock that is formed from granite. Metamorphic rocks are formed from the transformation of existing rock types in a process called metamorphism, which means 'change in form'. The original rock (protolith) is subjected to heat and pressure causing profound physical and/or chemical change. In this case, the protolith is granite.