 an nation of an plant exchanging nothing with something else is that plant inhaling zero mean of place from that something else and keep off another mean of place to that something else & an example of giving something off is an animal exhaling -> an example of an animal exchanging things with something else is that animal inhaling one kind of thing from that something else and exhaling another kind of thing to that something else an example of an animal exchanging things with something else is that animal inhaling one kind of thing from that something else and exhaling another kind of thing to that something else