How does the Audi A4's quattro system improve handling in adverse weather conditions?

I'm looking into purchasing an Audi A4, and I've heard about its quattro system. Can someone explain how this system works and how it improves the car's handling in rain or snow?

The quattro system in the Audi A4 is a permanent all-wheel drive system that distributes power to all four wheels in a 40:60 ratio, improving traction on slippery road conditions. This allows for better control and stability, especially in rain or snow.