Which term describes an organism that relies on other organisms for energy and food supply?

• A. Autotroph
• B. Heterotroph
• C. Producer
• D. Saprotroph

Answer: (B)

The concept being tested is how organisms obtain energy and organic matter. An organism that relies on other organisms for energy and food supply is a heterotroph. They cannot make their own energy-rich molecules from inorganic sources, so they must ingest or absorb preformed organic material provided by others. In contrast, autotrophs—often called producers—use light or inorganic chemicals to synthesize their own organic molecules. Saprotrophs are a specific type of heterotroph that digests and feeds on dead or decaying matter, but the general term for relying on others for energy and nutrients is heterotroph.