Autotrophs are organisms that:

• A. Must consume other organisms for energy
• B. Respond to their environment
• C. Are unable to produce their own food
• D. Are able to produce their own food (plants, algae, cyanobacteria)

Answer: (D)

Autotrophs make their own organic molecules from inorganic sources by using energy from light or from chemical reactions. This means they can convert carbon dioxide and other inorganic inputs into sugars and other nutrients, forming the base of many ecosystems. Plants, algae, and cyanobacteria are classic examples that use light-driven photosynthesis, while some bacteria use chemical energy to power chemosynthesis.

Because of that ability to synthesize their own food, autotrophs are the producers in ecological communities. The other statements describe characteristics that don’t define autotrophy: needing to consume other organisms points to heterotrophs, reacting to the environment is a general trait of many organisms, and being unable to produce their own food is the opposite of what autotrophs do.