Final answer:
Animals and other heterotrophs rely on autotrophs that carry out photosynthesis. Autotrophs like plants produce their own food and provide an energy source for heterotrophs, which cannot synthesize their own food.
Step-by-step explanation:
Autotrophs are organisms like plants, algae, and certain types of bacteria such as cyanobacteria that can produce their own food through photosynthesis, which is the process of converting light energy into chemical energy in the form of sugars or carbohydrates. These organisms are called "self-feeders" because they can create their own energy sources.
In contrast, heterotrophs are organisms that cannot produce their own food and must obtain energy by consuming other organisms. They are also termed "other feeders" as their food comes from other living things. All animals, including humans, fungi, and most other bacteria, are examples of heterotrophs that depend on the carbohydrates produced by autotrophs.