Here's why:
* Concrete nouns refer to things that can be touched, seen, smelled, tasted, or heard. Dinosaurs, while extinct, were real physical creatures.
* Abstract nouns refer to ideas, qualities, or concepts that cannot be touched, such as happiness, freedom, or love.
Even though dinosaurs are extinct, they were tangible beings. We can see their fossils, learn about their anatomy and behavior, and even recreate their appearance. This makes "dinosaur" a concrete noun.