Baruch is interested in the carbon cycle. He learns that carbon enters the forest from the atmosphere by the sugar-making process of

Photosynthesis is a sugar making process in which carbon is used in the form carbondioxide from the atmosphere and water is absorbed by the plant from the soil. When these two materials combine with each other, it produces oxygen and glucose. Oxygen is released in the atmosphere while glucose which is a monosaccharide is stored in different parts of plant body such as roots and stems.

Photosynthesis.

Explanation:

In photosynthesis;    6CO₂ + 6H₂O  →  C₆H₁₂O₆ + 6O₂

Here: CO₂ is carbonioxide, H₂O is water        ==> Reactants

         C₆H₁₂O₆ is simple sugar, O₂ is Oxygen ==> Products

Plants use their chlorophyll to trap Light energy that they use in breaking down the combination of "water" and "carbon dioxide".

The result of this process is "Simple Sugar" and Oxygen is emitted as the by-product.

the answer would be d : p