Answer:
heterotroph, primary consumer, eukaryote, herbivore.
Explanation:
Eukaryote is a unicellular or multicellular being that has a nuclear membrane, that is, its cell nucleus is separated from the cytoplasm by a membrane, unlike prokaryotes, which do not have a nuclear membrane. As we know animal cells have a separate nucleus from cytoplasm, as red squirrels are animals, we can say that they are eukaryotes.
Heterotrophs are living things that are unable to produce their own food and therefore need to ingest or absorb preformed organic molecules from other living things to obtain energy and synthesis of the biomolecules they need. As we can see from the question above, red squirrels do not produce their food as they feed on white spruce, so we can say that squirrels are heterotrophs.
In addition, we can say that red squirrels are herbivores, as the white spruce is a tree and herbivores are animals that feed exclusively on vegetables.
Finally, we can say that red squirrels are primary consumers. This is because primary consumers are those heterotrophic beings that feed on producers, that is, on plants and algae. As can be seen, these are herbivorous animals.