Question

The universe could be considered an isolated system because

1many people think that no energy or matter exists outside the universe.

2energy and matter are created in the universe and flow freely into and out of the universe.

3 energy is created outside the universe and matter is created within the universe.

4energy is created in the universe and matter is transferred out of the universe.

Answer 1

An isolated system is defined as a system that does not interact with the surroundings. Although not very well phased, (a) id the best one to choose. it will indicate interacts and surroundings.

Answer 2

The universe is considered to be an isolated system because
as far as we know ... or most likely can ever know ... no energy
or matter exists outside the universe.