What distinguishes an autotroph from a heterotroph?

The distinction between autotrophs and heterotrophs lies in their methods of obtaining energy. Autotrophs are organisms that can produce their own food through processes such as photosynthesis or chemosynthesis. They are capable of converting inorganic substances, such as carbon dioxide and water, into organic compounds like glucose, utilizing external energy sources, typically from sunlight. On the other hand, heterotrophs cannot synthesize their own food and must rely on consuming other organisms, whether they be plants, animals, or decomposed organic matter, to obtain the nutrients and energy they need to survive.

While some other choices touch on aspects of these two groups, they do not accurately capture the overarching definition that sets them apart. For example, not all autotrophs require sunlight, as some can derive energy from chemical processes in environments devoid of light. Similarly, not all heterotrophs are animals; there are many heterotrophic plants and fungi as well. Moreover, while photosynthesis is a method used by many autotrophs (particularly plants), it does not encompass the entire group, as some autotrophs do not engage in this process and instead rely on different means of energy acquisition. Thus, the key differentiator is indeed that autotroph