Femur - The thighbone. Fenestra - An opening in the skull. Fibula - The calf bone in the leg. Fossil - A fossil is any trace of life from the geologic past. It may even be a track or a trail, a burrow or a nest, a footprint.
Scientists generally define fossils as being at least ten thousand years old.
A group of closely related organisms within a family. A genus consists of one or more species. In print, the name of a genus appears in italics with a capital first letter. Gizzard - A thick walled, muscular bulge in the gut, with a tough, horny lining that helps grind food up. Occurs in birds and some dinosaurs.