Question

Which of the following best summarizes the effects that plants have on the global carbon cycle?

Plants perform both photosynthesis and cell respiration and cause a net increase of carbon in the atmosphere.
Plants perform photosynthesis, adding carbon to the atmosphere.
Plants perform both photosynthesis and cell respiration and cause a net decrease of carbon in the atmosphere.
Plants perform cell respiration, removing carbon from the atmosphere.

Answer 1

I believe the answer is D, if not it should be C.

Answer 2

plants perform both photosynthesis and cell respiration and cause a net decrease of carbon in the atmosphere