A possessive pronoun is a part of speech that attributes ownership to someone or something. Like any other pronoun, it substitutes a noun phrase and can prevent its repetition. For example, in the phrase, "These toys are mine, not yours", the words "mine" and "yours" are possessive pronouns and stand for "my toys" and "your toys, " respectively.
1. A possessive pronoun differs from a possessive adjective.
Examples:
What color is your brother's jacket?
His jacket is black.
(your and his are possessive adjectives; your and his modify the noun jacket in both examples)
What color is yours?
Mine is blue.
(yours and mine are possessive pronouns - yours functions as a subject complement in the first example; mine functions as a subject in the second example)
2. "It's" is not a possessive pronoun or adjective; it is a contraction of it is or it has. The correct form is 'its'.
Example:
It's not my book = it is not my book
It's got five bedrooms = it has got five bedrooms
Its got beautiful feathers = the bird has beautiful feathers.