Humans, when exhaling release carbon which helps them to make sugar, and as a biproduct plants release oxegen which humans inhale.
The cardiovascular system I think. Hope this helps
Why won’t it let me answer
Answer:
Like bees and other pollinators, butterflies pick up pollen while they sip a flower's nectar. Once they're off to another plant, the pollen goes with them, helping to pollinate the plant species.
Explanation: