What is the Quattro system in an Audi A7?

I've heard about the Quattro system in Audi vehicles, but I'm not sure what it does. Can someone explain the details of this system and why it is unique to Audi A7 models?

The Quattro system is a four-wheel drive system that is exclusive to Audi vehicles. It distributes power to all four wheels, providing improved traction and stability on different road surfaces and weather conditions. As for Audi A7 models, the Quattro system is unique because it can actively adjust the torque distribution between the front and rear axles, creating a more balanced and efficient driving experience.