Singular forms and possessive forms are terms for nouns and pronouns.
The word 'not' is an adverb, a word used to modify a verb, an adjective, or another adverb. Examples:
modifies a verb: This is not a good day.
modifies an adjective: He is not my boyfriend.
modifies an adverb: We are moving but not very far.
Quantum is singular, not singular possessive. The singular possessive form is quantum's.
The singular possessive form of "test" is "test's".
The singular possessive pronouns are "my," "mine," "your," "yours," "his," "her," and "its."
The singular possessive of "ant" is "ant's" and the plural possessive is "ants'".
Museum is singular. Museum's is singular possessive. Museums is plural. Museums' is plural possessive.
The singular possessive form of "classmate" is "classmate's."
Taco's is the singular possessive.
The singular possessive of dish is dish's
The singular possessive is Martin's.
The singular possessive is fish's.
Grave's is the singular possessive.
Buzz's is the singular possessive.