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.
Avoid touching it, if a mole is picked at and is expanding this can becaome a serious problem causing infection if picked at, if it continues to grow you might needd to see a doctor or a dermatologist
