Consider the roles of ATP and the nitrogenase enzyme complex in nitrogen fixation. How do these components interact to facilitate the conversion of nitrogen gas into ammonia, and what is the implication for energy consumption?

• A. Nitrogenase uses light energy instead of ATP, reducing energy consumption
• B. Nitrogenase functions without ATP, indicating low energy demand
• C. ATP is produced by nitrogenase, reducing energy demand
• D. Nitrogenase catalyzes the reaction using ATP, indicating high energy demand

Answer: (D)