40. Of the following, which is a reactant in the process of photosynthesis that is acquired by plants from the atmosphere?
Answer: D
Carbon dioxide is a reactant in the process of photosynthesis acquired by plants from the atmosphere.
Plants absorb carbon dioxide from the atmosphere, which is essential for the process of photosynthesis, allowing them to produce glucose and oxygen.
A) ATP
ATP is not a reactant in photosynthesis; rather, it is an energy carrier produced during the light-dependent reactions. While ATP is utilized in the Calvin cycle to convert carbon dioxide into glucose, it is not acquired from the atmosphere.
B) NADPH
NADPH is also not a direct reactant obtained from the atmosphere. It is generated during the light-dependent reactions of photosynthesis and functions as a reducing agent in the Calvin cycle, but it does not come from the atmosphere.
C) Oxygen
Oxygen is a byproduct of photosynthesis, released into the atmosphere during the light-dependent reactions. It is not a reactant that plants absorb from the atmosphere; rather, it is produced as a result of the splitting of water molecules.
D) Carbon dioxide
Carbon dioxide is the correct answer as it is a key reactant in photosynthesis. Plants take in carbon dioxide from the atmosphere through small openings in their leaves called stomata, which is then used in the Calvin cycle to synthesize glucose.
Conclusion
Carbon dioxide is essential for photosynthesis, making it the only correct answer in this context. ATP and NADPH are products of the process, while oxygen is a byproduct. Therefore, all other options fail to meet the criteria of being a reactant acquired from the atmosphere.