- To compact something means to compress something
- Sedimentary rocks are formed by sediment compacting together
- Therefore, sedimentary rocks are formed by sediments being compressed together

- Sedimentary rocks are formed by sediments being compressed together
- Sediment is a kind of small particle
- Hence, sedimentary rocks are formed by small particles being compressed together

- Sedimentary rocks are formed by small particles being compressed together
- Sedimentary rocks are formed in layers
- Hence, sedimentary rocks are formed by small particles being compressed together in layers

So, sedimentary rocks are formed by small particles being compressed together in layers
Question
There are several different types of rock. Each type of rock is formed under different conditions. How are sedimentary rocks, such as shale and sandstone, formed?

Context
- Sedimentary rocks are formed in layers 
- Sediment is a kind of small particle 
- To compact something means to compress something 
- Sedimentary rocks are formed by sediment compacting together