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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
