Answer the following question given this paragraph: 

Life is complex, and there are millions of species alive today. Many millions more lived in the past and then went extinct. Organisms include microscopic, single-celled organisms. They also include complex, multicellular animals such as you. Clearly, life science is a huge science. That’s why a life scientist usually specializes in just one field within life science. Dr. Smith, for example, specializes in ecology. You can see the focus of ecology and several other life science fields in Table below . Click on the links provided if you want to learn about careers in these fields.


Q: What do you call a species that has died out in the past?


A:
extinct