And another question, why does Merab always fight in Las Vegas his recent fights? I don't remember him fighting somewhere else recently.
The UFC performance institute (UFC PI) is located in vegas.
Many UFC fighters live and train in vegas as they can receive free training, free meals, free supplements, free medical support & other benefits at the UFC PI.
Vegas is where the UFC has most of its infrastructure and amenities.
Vegas is a great tourist and gambling destination. Which is why it was once called the fight capital of the world.