Which of the following is NOT considered an autotroph?

Autotrophs are organisms that can produce their own food using inorganic substances. They typically perform photosynthesis or chemosynthesis to convert carbon sources into organic molecules, which provides energy for growth and metabolism.

In the context of the options provided, animals are not considered autotrophs because they cannot produce their own food. Instead, animals are heterotrophs, which means they obtain their energy and nutrients by consuming other organisms, whether they are plants, animals, or decomposing organic matter.

In contrast, algae and plants are well-known examples of autotrophs because they can photosynthesize, using sunlight to convert carbon dioxide and water into glucose and oxygen. Some bacteria, particularly those involved in chemosynthesis, are also autotrophic as they can derive energy from inorganic chemical reactions. Thus, animals stand out as the only option that does not fit the definition of autotroph.