Which term best describes an organism that is photosynthetic but can also use organic compounds for energy in the absence of light?

The term that best describes an organism that is photosynthetic but can also utilize organic compounds for energy in the absence of light is "photoheterotroph." Photoheterotrophs can harness light energy to drive their metabolic processes but have the flexibility to absorb organic compounds when light is not available. This dual capability allows them to thrive in varying environmental conditions, using light for energy when it's available and organic sources when it is not.

In contrast, photoautotrophs primarily use light energy to convert inorganic substances, such as carbon dioxide, into organic compounds, relying heavily on photosynthesis to generate their energy and building blocks. Chemoautotrophs obtain energy by oxidizing inorganic compounds and do not rely on light or organic compounds. Chemoheterotrophs, on the other hand, acquire both energy and carbon from organic compounds but do not utilize photosynthesis at all. Thus, "photoheterotroph" is the most accurate term for organisms that require both sunlight and organic compounds for energy.