Of the following, which is a reactant in the process of photosynthesis that is acquired by plants from the atmosphere?

ATP (adenosine triphosphate) is not a reactant taken from the atmosphere but rather an energy carrier produced during photosynthesis. It is generated in the light-dependent reactions and subsequently utilized in the Calvin cycle to help convert carbon dioxide into glucose. Thus, ATP is a product of photosynthesis, not a reactant.

NADPH is also not acquired from the atmosphere; it is produced during the light-dependent reactions of photosynthesis. This molecule serves as a reducing agent in the Calvin cycle, facilitating the conversion of carbon dioxide into glucose. Therefore, NADPH is a product generated within the plant rather than a reactant sourced from the environment.

Oxygen is a byproduct of photosynthesis, released into the atmosphere when water molecules are split during the light-dependent reactions. While it is produced during the process, it is not a reactant that plants acquire from the atmosphere. Instead, oxygen is released as a result of the chemical reactions that occur during photosynthesis.