Your answer is a , atoms .
The elodea is getting the carbon dioxide from its environment like when underwater animals breathe out carbon dioxide the plants will use that carbon dioxide. The plants can also get the carbon dioxide from the atmosphere which can "dissolve" in water.
Sex is a reproduction system involving both male and female to partake in sexual activity intercourse to create an offspring between the two beings creating a living organism
I believe that would be option B inguinal and popliteal.
Hope it helps!
