You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?

• A. Even though it cannot carry out the light reactions, the plant can still produce sugars because the Calvin cycle does not require light.
• B. Even though the plant received no visible light, it was able to use the short-wave part of the electromagnetic spectrum (gamma rays and X-rays) to carry out photosynthesis.
• C. When light energy is not available, plants can derive energy from inorganic molecules.
• D. None of the listed responses is correct.
• E. While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.