An organism requiring complex organic compounds for food is called a heterotroph.

Here's why:

* Heterotrophs cannot produce their own food through processes like photosynthesis. They rely on consuming other organisms (plants, animals, fungi, bacteria) to obtain the necessary energy and nutrients.

* Complex organic compounds are molecules containing carbon and hydrogen, often with oxygen, nitrogen, and other elements. These are the building blocks of living organisms and provide the energy and materials heterotrophs need to survive.

Examples of heterotrophs:

* Animals: Lions, humans, fish, insects

* Fungi: Mushrooms, yeasts, molds

* Most bacteria: Decomposers, parasites

In contrast:

* Autotrophs, like plants and some bacteria, can produce their own food through photosynthesis, using sunlight, water, and carbon dioxide.