The eukaryotes that do not fit into any of the other three kingdoms fall into which group?

• A. Plants
• B. Fungi
• C. Animals
• D. Protists

Answer: (D)

Grouping eukaryotes that don’t fit the defining features of plants, animals, or fungi into Protists helps explain why this category exists. Plants are multicellular with cellulose cell walls and photosynthesis; animals are multicellular without cell walls and are typically mobile and ingestive; fungi are heterotrophs that absorb nutrients through their walls with chitin and hyphae. Many eukaryotes don’t match any of those distinct body plans or lifestyles, so they’re placed in a broad, diverse Protists group. This group includes organisms that can be unicellular or simple multicellular and can be photosynthetic or heterotrophic, such as algae and protozoa. Because these organisms don’t share the defining traits of the other three kingdoms, Protists is the best fit.