Question

which example is a closed system? (1 point)

○ a sealed jar of salad dressing

○ the atmosphere of a planet

○ a bowl of punch at a gathering

○ the human body

Explanation:

A closed system is one where matter cannot enter or leave, but energy can. A sealed jar of salad dressing doesn't allow matter (like the dressing or air) to enter or exit, so it's a closed system. The planet's atmosphere, a bowl of punch (people can take punch, adding/removing matter), and the human body (exchanges matter like breathing, eating) are open systems as they allow matter exchange.

Answer:

a sealed jar of salad dressing