Answer:
Rock cycle describes the concept in geology that shows the changes in the rock type in the geologic time.
Many processes undergoes in the rock cycle that leads to transition of rocks, the process that changes metamorphic rock to igneous rock is melting and crystallization. The metamorphic rock melts under high pressure and temperature and which crystallizes into a completely different kind of rock, called igneous rock.
One light-year is the distance that light travels in vacuum
in one year. It's a unit of distance.
