Ok I understand why the answer I marked, C was incorrect, specifically because of the last part of the sentence says "some clearly never were". However, the correct answer choice, option D also confuses me because it says that small amounts of the Co2 entered the soil from the atmosphere. The confusing part in all this is that the premise says the plants make the Co2 and put it into the atmosphere, so I do not understand completely why option D is correct. I understand why my answer of option C was incorrect, however.
Admin Note: Edited title. Please use the format: "PT#.S#.Q# - brief description of the question."