Here's why:
* Abstract nouns represent concepts, ideas, or qualities. They are not physical things you can touch.
* "Appreciate" as a verb describes the action of recognizing the value or worth of something.
* "Appreciate" as a noun refers to the feeling or act itself.
Example:
* Verb: I appreciate your help.
* Noun: She showed her appreciation by sending a thank-you note.
In the second sentence, "appreciation" refers to the feeling of being grateful and is therefore an abstract noun.