The word 'it' is a singular personal pronoun, but 'it' is not a possessive form.
The possessive form for the pronoun it is its.
Possessive pronouns and possessive adjectives do not use an apostrophe to show possession. Examples:
The horse threw its rider.
The dog is bothering you because its bowl is empty.
The form using an apostrophe, it's, is a contraction, a shortened for for it is. Example:
What time is it? It's four o'clock. (It is four o'clock)
The singular possessive form of "test" is "test's".
The singular possessive pronouns are mine, yours, his, hers, and its. The singular possessive adjectives are my, your, his, her, and its.
The singular possessive is ant's.The plural possessive is ants'.
Museum is singular. Museum's is singular possessive. Museums is plural. Museums' is plural possessive.
The singular possessive of dish is dish's
Taco's is the singular possessive.
The singular possessive form is classmate's.
The singular possessive is biker's; the plural possessive is bikers'.
The singular possessive is fish's.
Grave's is the singular possessive.
The singular possessive is Martin's.
Buzz's is the singular possessive.