1.My mouth is bigger than yours.
An elephant is bigger than a mouse.
A pig is bigger than an ant.
I want the bigger one.
The animal is much bigger.
His car is the bigger one.
2.The elephants are the biggest animals.
This is one of the biggest animals.
They have made the biggest house in the world
He has made the biggest decision.
The biggest one was chosen.
They have the biggest one.