Question

An isolated system is best characterized as a system in which: Energy can freely enter and leave but matter cannot. Matter and energy can freely enter and leave. Matter can freely enter and leave, but energy cannot. Energy and matter cannot enter or leave.

Answer 1

In physical science there are two types of "isolated systems"

1. Being a Physical System in which it is so far removed from other systems that it does not react with any of them.

2. Being a Thermodynamic System in which it is enclosed by rigid immovable walls of which neither mass nor energy can flow through.

I believe in this case although not stated that it would refer to a Thermodynamic System which would leave you with the only plausible answer as ENERGY AND MATTER CANNOT ENTER OR LEAVE.

None of the other answers make sense. Even if it were referring to Physical. Physical does not react with anything at all. An as you can see Thermodynamic does not allow for anything to pass through or leave.

Answer 2

Correct answer: D). Energy and matter cannot enter or leave.

An isolated system is a system in which neither the energy nor the matter can enter or leave the system. As a result of that,  the total mass of the system remains unchanged.

There is a change in the species present, But, the total mass present will not change based on the law of conservation of matter and energy.