How does the Audi A2's aluminum frame contribute to its lightweight design?

I've heard that the Audi A2 has an aluminum frame, but I'm not sure why or how that affects the car's weight. Can anyone explain this for me?

The aluminum frame of the Audi A2 plays a crucial role in its lightweight design. Aluminum is much lighter than traditional steel frames, so it allows the car to be more fuel-efficient and have better handling.

In addition to being lightweight, the aluminum frame of the Audi A2 also increases the car's rigidity and stiffness. This makes the car safer and more durable on the road.