Final answer:
Organisms that use organic compounds for both energy and carbon are chemoheterotrophs. The correct answer to which type of organism uses organic compounds as both an energy source and a carbon source is (c) Heterotrophs.
Step-by-step explanation:
The organism that uses organic compounds as both an energy source and as a carbon source is known as a chemoheterotroph. These organisms must rely on organic molecules such as sugars and cannot produce their own organic matter through processes like photosynthesis.
Chemoheterotrophs must consume organic building blocks that they cannot synthesize themselves. Examples of such organisms include humans and most eukaryotes. This is in contrast to photoautotrophs such as plants and certain bacteria that use light energy and carbon dioxide to create organic materials, and chemoautotrophs that use inorganic compounds to produce organic compounds.
The correct answer to the question is (c) Heterotrophs, which fully describes organisms that utilize organic compounds for both their energy and carbon needs.