Answer:
My guess would be H₂O/ water, since osmosis is a form of passive transport and I can't see the model the question references. Gases like O₂/ oxygen, CO₂/ carbon dioxide, and simple sugars like glucose can also pass through a cell membrane with passive transport though.
Answer is C hope it helps
Im really good at crosswords, e-mail a copy & i’ll fill it out for you
"Their habitats may range from the surface water to the ocean trenches. Marine organisms are classified<span> by how they move and where they live."
Hope This somehow helps~
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