Question

a closed system is one that does not receive input from outside the system. for example, the earth is a closed system for matter because the amount of matter on the earth does not change. what is another example of a closed system? a plant releasing oxygen into the atmosphere an unopened jar of peanut butter

Explanation:

A closed system does not receive input from outside. An unopened jar of peanut butter has no exchange of matter with the outside (assuming it's sealed properly). A plant releasing oxygen is part of an open system as it interacts with the atmosphere (taking in carbon dioxide, releasing oxygen, etc., which are exchanges with the outside).

Answer:

An unopened jar of peanut butter