differemce between demonstraive pronoun and relative pronoun
A Demonstrative Pronoun points to the object which it refers.
Example: This is my house.
Here, the pronoun 'this' points to the object that is 'house'.
A Relative Pronoun points or refers to the noun going before it, which is called its antecedent.
Example: I have bought the book that I wanted.
Here, the pronoun 'that' relates to the noun going before it i.e. to 'the book'