Answer:
Heterotrophs are organisms that are incapable of photosynthesis and therefore must obtain energy and carbon from food by consuming other organisms. The Greek roots of the word heterotroph mean "other" (hetero) "food" (trophy), which means that their food comes from other organisms. Although the food organism is a different animal, this food attributes its origin to autotrophs and the photosynthetic process. Humans are heterotrophs, like all animals. Heterotrophs depend directly or indirectly on autotrophs. Deer and wolves are heterotrophs. A deer gains energy by eating plants. A wolf that eats a deer originally gets its energy from the plants that the deer eats. The plant's energy comes from photosynthesis and is, therefore, the only autotrophic plant in this example (Figure 5.3). According to this consideration, all the foods that humans eat can also be traced back to autotrophs that carry out photosynthesis.