How might you explain to her that that is not exactly true, depending on how you classify animals?

 A friend says that the Dinosaurs all went extinct millions of years ago. How might you explain to her that that is not exactly true, depending on how you classify animals? Upload your argument as to why Dinosaurs are or are not extinct. Think for yourself (and use the content in your text) please, copied answers from web searches will not earn points. 

500 words