How can one type of rock be transformed into another type of rock

It does this because The rock cycle by definition is a natural process by which sedimentary, igneous, and metamorphic rocks are created, changed from one type to another, and destroyed.The three main rock types are igneous, sedimentary, and metamorphic. Crystallization, erosion and sedimentation, and metamorphism transform one rock type into another or change sediments into rock. The rock cycle describes the transformations of one type of rock to another.There are three kinds of rock: igneous, sedimentary, and metamorphic. Igneous rocks form when molten rock (magma or lava) cools and solidifies. Sedimentary rocks originate when particles settle out of water or air, or by precipitation of minerals from water. They accumulate in layers.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.

the answer is:  

line graphs show patterns in data with variables that change over time; whereas, circle graphs show data as parts out of a whole (such as out of 100%).