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?
an unopened jar of peanut butter
a plant releasing oxygen into the atmosphere

Explanation:

An unopened jar of peanut butter does not receive input from outside as it is sealed. A plant releasing oxygen is an open - system as it exchanges matter (oxygen) with the outside atmosphere.

Answer:

An unopened jar of peanut butter