Which term describes an organism that cannot synthesize its own food and must ingest others?

• A. Autotroph
• B. Producer
• C. Primary consumer
• D. Heterotroph

Answer: (D)

Heterotroph is the term for an organism that cannot synthesize its own food and must obtain organic material by ingesting or absorbing it from other organisms. They rely on consuming plants, animals, or the waste and dead matter around them to get carbon and energy. This distinguishes them from autotrophs, which can make their own organic molecules from inorganic sources (typically via photosynthesis or chemosynthesis). Producers are usually autotrophs at the base of ecosystems, while primary consumers are organisms that eat producers (like herbivores). So the description—unable to synthesize their own food and needing to ingest others—best matches heterotroph.