Is nervous system a common noun?

Here's why:

* Common nouns refer to general, non-specific things or ideas. They are not capitalized unless they are at the beginning of a sentence.

* "Nervous system" refers to the general concept of a network of nerves and tissues that control bodily functions. It's not a specific, unique individual.

Examples:

* Common noun: "The nervous system is vital for our survival."

* Proper noun: "The National Institutes of Health are researching the nervous system."

Let me know if you have any other grammar questions!