Which term refers to organisms that use light to synthesize organic compounds?

• A. Autotrophic
• B. Heterotrophic
• C. Photosynthetic Bacteria
• D. Chemotrophic

Answer: (C)

Phototrophy is about using light energy to drive the production of organic molecules. Organisms that do this are photosynthetic or phototrophic. Among the options, photosynthetic bacteria directly names those that use light to build organic compounds through photosynthesis, which fits the description precisely. Autotrophic describes making own organic matter from inorganic sources, but it doesn’t specify the energy source, since some autotrophs are chemosynthetic. Heterotrophic organisms rely on already-made organic compounds, and chemotrophic organisms obtain energy from chemical reactions rather than light. So the best fit is photosynthetic bacteria.