(d) : Living fossil is a term for any living species (or clade) of organism which closely resembles species otherwise only known from fossils and has no close living relatives. These species have all survived major extinction events, and generally retain low taxonomic diversities. Some examples of living fossils in animals are coelocanth, coral (polyp), crocodylia (crocodiles, gavials and alligators), horseshoe crab (Limulus polyphemus), monotremes (Platypus and Echidna), snout-nosed frog ( Nasikabatrachus sahyadrensis ). Archaeopteryx is the earliest and most primitive known bird to date. It lived in the Jurassic Period around 150-155 million years ago. It has feathers and wings but it also had teeth and a skeleton similar to a small carnivorous dinosaur, therefore, it had both bird and theropod dinosaur features. Archaeopteryx is a powerful piece of evidence that shows that birds have evolved from dinosaurs.