The singular possessive is duke's.
"Firefly's" is a singular possessive noun.
The singular possessive noun is stepchild's.
No, "tomb" is a singular common noun, not a possessive noun.
The singular noun is tooth.The singular possessive noun is tooth's.
Yes, "vest's" is the singular possessive form of the noun "vest."
The singular possessive noun of grandmother is grandmother's.
The singular possessive of the noun "arch" is "arch's."
No, the noun creatures' is the possessive form of the plural noun creatures.The singular possessive form is creature's.
The singular noun possessive form of "robes" is "robe's."
No, "she's" stands for she is. The singular possessive noun for a female is her or hers.
Yes, "story's" is the singular possessive form of the noun "story."