Here's why:
* Abstract nouns represent concepts, qualities, or ideas that cannot be touched or seen (e.g., love, happiness, freedom).
* "Heeded" is the past participle of the verb "heed," meaning to pay attention to or take notice of.
While "heed" itself can be considered a noun representing the act of paying attention, "heeded" is a verb form, not a noun.
Example:
* "Heeded" - "The warnings were heeded by the residents." (Past participle of the verb "heed")
* "Heed" (as a noun) - "The driver paid no heed to the stop sign." (The act of paying attention)
Let me know if you have any other questions!