Final answer:
A unicellular heterotrophic eukaryote that ingests its food is classified as a heterotroph, which relies on consuming organic materials from other organisms for sustenance.
Step-by-step explanation:
A unicellular heterotrophic eukaryote that ingests its food would be classified as a heterotroph. This is because heterotrophs are organisms that obtain their carbon from organic compounds, typically from other organisms. Unlike autotrophs, which can synthesize their own food using inorganic carbon sources such as CO2, heterotrophs must consume other organisms to meet their carbon and energy needs. In addition, the term 'unicellular' indicates that the organism is composed of a single cell, and 'eukaryote' suggests that this cell has a nucleus and other membrane-bound organelles. Examples of unicellular heterotrophic eukaryotes that ingest their food include various types of protozoa, such as amoebas which use phagocytosis to consume food particles.