sentences: a dinosaur is a kind of extinct animal & a bone is a part of some animals & an nation of a factory is the parts of an extinct plant ->  the bones of dinosaurs are an example of fossils  the senses of conjugate are an nation of user & index fossils can be used to determine the approximate age of other fossils in that area -> index fossils can be used to determine the approximate age of the fossils of the bones of dinosaurs