Final answer:
The correct answer to what metamorphic rocks are is E) B and C, which state they have mineral compositions and textures altered from those originally present due to increased temperature, pressure, and contact with fluids. The process is called metamorphism.
Step-by-step explanation:
Metamorphic rocks are types of rocks that have undergone a transformation due to increased temperature and pressure, or contact with chemically reactive fluids. You asked which statement correctly explains what metamorphic rocks are. The correct answer is E) B and C, meaning both B) 'have mineral compositions altered from those originally present by increased temperature and pressure' and C) 'have textures altered from those originally present by agents such as water and volatile magmatic fluids' are true. Metamorphic rocks are born out of a process called metamorphism, which triggers the recrystallization of minerals in a pre-existing rock, known as the protolith.
This process can lead to changes in mineral content, size, and the orientation of the minerals within the rock, producing a variety of metamorphic rocks such as schists, slates, and marbles, each with unique attributes based on their original rock type and the metamorphic conditions they encountered.