the universe evolved!

How do we respond to the atheist who says that the universe evolved?

Science does not say that the world moves from simple elements to more complex elements.
On the contrary
Science says that the world moves from complete complexity to simplification over time

This is known as the Second Law of Thermodynamics.
 To simplify this law:

If you had a glass of hot water in the room, the heat would move from the hot water to the atmosphere of the room until the temperature of the room is equal to the temperature of the cup, and so this law applies to everything in the universe and at one point everything will be equal in the universe, this moment will be the Thermal Death of Universe.

If it is eternal, the universe would have been suspended now - thermally dead - but in reality the universe is now less than the maximum entropy, and it has not reached the thermal death yet. Therefore, it is not eternal and has a fixed beginning with which time and place appeared.

But the universe appeared at the minimum of entropy, which means that it did not exist according to an earlier example 

By the way this is a law and not a theory
It applies to everything, to the atom and to the galaxy

This law is essential in proving that the idea of turning the world's parts into complexity, as the atheist imagines, is a fake idea that does not actually exist.

The universe is proceeding towards simplification rather than complexity.