dinosaur - n. one of many reptiles that lived on Earth millions of years ago​

evolve - v. to change or develop slowly often into a better, more complex, or more advanced state​

extinction - n. the state or situation that results when something (such as a plant or animal species) has died out completely​

fossil - n. something (such as a leaf, skeleton, or footprint) that is from a plant or animal which lived in ancient times and that you can see in some rocks​

marine mammal - n. Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. ​

mythological - adj. the myths of a particular group or culture​