A closed system is completely closed to the outside environment. Every interaction is transmitted inside that closed system.
The correct answer to
the question that is stated above is letter c, <span> the outer electron shell.</span>
Valence electrons occur<span> in the outermost shells of an </span>atom.
>> <span>Valence electrons are </span>electrons<span> that are associated with an </span>atom<span>, and that can participate in the formation of a </span>chemical bond.
This is true i think if that is a question