Metamorphic rocks form by:Selected answer will be automatically saved. For keyboard navigation, press up/down arrow keys to select an answer.aCrystallization from magma.bFragments of pre-existing rocks, minerals, and fossils "glued" together by steam.cChemical and textural alteration of pre-existing rocks due to high temperature and pressure, and possibly the exchange of fluids.dMetamorphosis of caterpillars to butterflies.eNone of the above

The correct answer is c. Metamorphic rocks form by chemical and textural alteration of pre-existing rocks due to high temperature and pressure, and possibly the exchange of fluids.

Here's a step-by-step explanation:

1. Metamorphic rocks start off as any type of rock, such as igneous, sedimentary, or even other metamorphic rocks. These are known as the parent rock or protolith.

2. The parent rock is subjected to extreme heat and pressure, often due to tectonic forces deep within the Earth's crust.

3. The high temperatures and pressures cause the minerals in the parent rock to rearrange themselves, creating a new texture. This process is known as recrystallization.

4. In some cases, fluids may also be involved in the metamorphic process. These fluids can cause chemical reactions that change the composition of the rock.

5. The end result is a metamorphic rock, which has a different texture and mineral composition than the original parent rock.