The complete question
What is meant by the statement "every metamorphic rock has a parent rock"? view available hint(s)
a) all metamorphic rocks are created only through the change of preexisting rock.
b) all metamorphic rocks form from the cooling of previously melted rock.
c) metamorphic rocks share no similarities with the original material from which they formed.
d) all metamorphic rocks are created only from previous metamorphic rocks.
e) all metamorphic rocks are created only through accumulation of pieces of previously existing rocks.
Every metamorphic rock has a parent rock
All metamorphic rocks are formed from preexisting rocks. The parents rocks might be sedimentary, igneous or even metamorphic. The parent rocks undergo deep burial where heat and pressure act on it to form metamorphic rock. The new rock may change in mineral assemblage or texture. The transformation usually takes place in the solid state. Example is the transformation of limestone to marble. Marble is a metamorphic rock.
Explanation:
a) all metamorphic rocks are created only through the change of preexisting rock.
All metamorphic rocks are formed from preexisting rocks. The rock might be sedimentary, igneous or even metamorphic rocks. The rock are changed by the process known as metamorphism. The changes occur during burial of the parent rocks where pressure and heat act on it.
b) all metamorphic rocks form from the cooling of previously melted rock.
Not all metamorphic rock are usually formed from the cooling of previously melted rocks. For examples igneous rocks are formed from the solidification of magma. The rocks where once semi liquid before it solidified to form igneous rocks. Metamorphic rocks are formed from these igneous rocks through cooling, the pressure that act on the parents rocks are not enough to melt it. The transformation to metamorphic rocks takes place in the solid state.
c) metamorphic rocks share no similarities with the original material from which they formed.
Metamorphic rocks are formed through the process of metamorphism. Metamorphism occurs after burial of the parent rocks. Heat and pressure act on the original rocks changing the mineral assemblage , texture or both to form a new kind of metamorphic rock. The new rock formed  might be different from the original rock in texture or mineral assemblage. This new rocks might end up not sharing any similarities with the original rock. But some metamorphic rocks share great similarities with the original rock.
d) all metamorphic rocks are created only from previous metamorphic rocks.
Metamorphic rocks can be created from previous metamorphic rocks if the pressure and temperature is right to form the new metamorphic rock. Not all metamorphic rocks are created from previously existing metamorphic rocks.
e) all metamorphic rocks are created only through accumulation of pieces of previously existing rocks.
Not all metamorphic rocks are created through the accumulation of pieces of previously existing rocks. But all metamorphic rocks are created from previously existing rocks.
