Question

Organisms that cannot make their own food and must obtain energy from external sources are called _______

Answer 1

Heterotrophs are organisms that obtain energy and carbon from food by consuming other organisms. They depend on autotrophs, either directly or indirectly. For example, a deer obtains energy by eating plants, and a wolf eating a deer obtains energy that originally came from the plants eaten by that deer.

Step-by-step explanation:

Heterotrophs are organisms incapable of photosynthesis that must therefore obtain energy and carbon from food by consuming other organisms. The Greek roots of the word heterotroph mean "other" (hetero) "feeder" (troph), meaning that their food comes from other organisms. Humans are heterotrophs, as are all animals and fungi. Heterotrophs depend on autotrophs, either directly or indirectly. For example, a deer obtains energy by eating plants. A wolf eating a deer obtains energy that originally came from the plants eaten by that deer. Using this reasoning, all food eaten by humans also links back to autotrophs that carry out photosynthesis.

Answer 2

Heterotrophs

Step-by-step explanation:

Autotrophs are organisms that are able to use a source of energy such as sunlight, to produce their own food. Heterotrophs cannot produce their own food and must rely on the foods they ingest for energy.