- Limestone is a kind of sedimentary rock
- Marble is a kind of metamorphic rock
- Hence, limestone is a kind of sedimentary rock and marble is a kind of metamorphic rock

- Sedimentary rocks are formed by deposition / cementation
- Metamorphic rocks are formed by rocks being exposed to extreme heat and pressure
- Therefore, sedimentary rocks are formed by deposition / cementation and metamorphic rocks are formed by rocks being exposed to extreme heat and pressure

- Limestone is a kind of sedimentary rock and marble is a kind of metamorphic rock
- Sedimentary rocks are formed by deposition / cementation and metamorphic rocks are formed by rocks being exposed to extreme heat and pressure
- Hence, limestone is a kind of sedimentary rock that is formed by deposition / cementation and marble is a kind of metamorphic rock that is formed by rocks being exposed to extreme heat and pressure

- Limestone is a kind of sedimentary rock that is formed by deposition / cementation and marble is a kind of metamorphic rock that is formed by rocks being exposed to extreme heat and pressure
- Class is a property of a rock and includes values of sedimentary / metamorphic / igneous
- Hence, limestone and marble are different classes of rock and are formed by different methods

- Limestone and marble are different classes of rock and are formed by different methods
- Class is a measure of how a rock is formed
- Hence, different classes of rocks are formed by different methods

So, different classes of rocks are formed by different methods
Question: Limestone is a sedimentary rock and marble is a metamorphic rock. Even though limestone and marble have the same chemical makeup, they are classified as different rocks because they
Context: - Class is a property of a rock and includes values of sedimentary / metamorphic / igneous 
- Sedimentary rocks are formed by deposition / cementation 
- Metamorphic rocks are formed by rocks being exposed to extreme heat and pressure 
- Class is a measure of how a rock is formed 
- Limestone is a kind of sedimentary rock 
- Marble is a kind of metamorphic rock