bones are part of some animals & animals are a kind of organism ->  bones are part of organisms  animals are a kind of organism & a shell is a part of some animals ->  shells are part of some organisms  bones are part of organisms & shells are part of some organisms & fossils are the remains of organisms or part of organisms & plants are a kind of organism ->  bones remains, shells remians, and plants remains are fossils  bones remains, shells remians, and plants remains are fossils & containing fossils is a kind of characteristic of sedimentary rock -> if a rock contains bones remains, shells remians, or plants remains, then the rock is a sedimentary rock