The universe could be considered an isolated system because many people believe that no energy or matter exist outside the universe. energy and matter are created in the universe and flow freely into and out of the universe. energy is created outside the universe and matter is created within the universe. energy is created in the universe and matter is transferred out of the universe.

Explanation :

In physics, a system in which net external force is equal to zero is called as an isolated system.

It is a well known fact after the universe that the net energy of the system is constant.

So, our universe could be considered as an isolated system because energy or matter doesn't exchange with surroundings. So, it is believed that no energy or matter exists outside the universe.

chemical properties of thing

no sign of dia of fuel cell