Biology STAAR (State of Texas Assessments of Academic Readiness) Practice Test

The primary distinction between autotrophs and heterotrophs lies in their method of obtaining food. Autotrophs are organisms that can produce their own food using light, water, carbon dioxide, or other chemicals. This process often involves photosynthesis, as seen in plants, algae, and some bacteria, or chemosynthesis, as seen in certain bacteria that derive energy from chemical reactions.

On the other hand, heterotrophs are unable to produce their own food and must obtain organic compounds by consuming other organisms or organic matter. This includes animals, fungi, and many bacteria that rely on autotrophs or other heterotrophs for their energy and nutritional needs.

The other options do not accurately reflect the fundamental difference between these two categories of organisms. For example, reproduction methods, habitat preferences, and cellular structures can vary widely within both autotrophs and heterotrophs and are not the primary criteria for distinguishing them.