Here's why:
* Common Nouns: "Dinosaur" is a common noun, referring to a general category of extinct reptiles. Common nouns are not capitalized unless they are at the beginning of a sentence.
* Proper Nouns: Proper nouns are names of specific people, places, or things. They are always capitalized. For example, if you were talking about a specific dinosaur species, like "Tyrannosaurus Rex", you would capitalize "Tyrannosaurus" and "Rex".
Examples:
* Correct: "The dinosaur was a massive creature."
* Incorrect: "The Dinosaur was a massive creature."
* Correct: "We saw a Tyrannosaurus Rex skeleton at the museum."
Let me know if you have any other questions!