A fossil is the remains of an animal or plant that lived long ago. Most fossils are created from the hard parts of ananimal’s body,__41__ bones, shells, or teeth. Some are__ 42__  , like dinosaur footprints. Some are so tiny that you need a microscope to__ 43__  them. Most fossils are found in rocks __44__ from the mud or sand that collects at the bottom of oceans, rivers, and lakes. Fossils provide scientists with__45__   to ancient animals.