The possessive form of the noun brother-in-law is brother-in-law's.
The possessive form of the noun sister-in-law is sister-in-law's.
Examples:
My brother-in-law's office is in this building.
This cake is my sister-in-law's recipe.
The possessive form of the noun brother is brother's.The possessive form of the coat of my brother is my brother's coat.
The possessive form for the noun brother is brother's.Example: My brother's daughter is my niece.
The singular possessive form for brother is brother's; for example:I drive my brother's car.
The possessive form is animal's behavior.
The word brother's is singular possessive. The plural possessive form is brothers'.
The possessive form is 'the animal's behavior'.
It is brother's
my friend's brother
The plural possessive form of the behavior of the animals is the animals' behaviour. Therefore the possessive noun is animals'.
The possessive form of the singular noun brother-in-law is brother-in-law's.example: I'm making a cake for my brother-in-law's birthday.
The possessive form for the tool kit of his brother-in-law is his brother-in-law's tool kit.
The possessive form of the proper noun Benjamin is Benjamin's.Example: Have you met Benjamin's brother?