If I'm correct then marshmallow is a common noun like, I love to eat marshmallows. It would be proper if using the name of marshmallows like, these are Jet Puffe d Marshmallows.
Yes, the word 'marshmallow' is a common noun, a general word for a marshmallow plant, or a soft confectionery made from a mixture of sugar, albumen, and gelatin.
"Park Avenue" is a proper noun, because it is a place. Proper nouns like this should always be capitalized.
It is a proper noun, because it is the name of a specific thing.
proper
Proper noun
Pencil proper or common noun
it's a common noun. a proper noun would be Spider-Man.
Proper noun or common noun
The noun cassette is a common noun.
a common noun?
Camel is a common noun.
The answer is proper noun. Examples of common noun and proper noun are: Proper noun: Mary Collins Common noun: monkey