Which term describes organisms that produce their own food from light or inorganic chemical energy?

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

Answer: (A)

Autotrophy is being described here. Autotrophs make their own organic matter by tapping energy from light or from inorganic chemical reactions. In photosynthesis, light energy drives the conversion of carbon dioxide and water into sugars, with oxygen released as a byproduct—plants, algae, and cyanobacteria are classic examples. Some organisms use energy from inorganic chemicals (chemosynthesis) to fix carbon into organic molecules, which is how certain bacteria live in environments like deep-sea vents. Because they produce the organic compounds that fuel the rest of the ecosystem, autotrophs are the primary producers. In contrast, heterotrophs must obtain carbon-rich compounds by consuming other organisms. So the best term for organisms that produce their own food from light or inorganic chemical energy is autotroph.