Question

which level of classification includes the greatest variety of organisms?
class
phylum
order
kingdom

Explanation:

In biological classification (taxonomy), the hierarchy from broadest to most specific is kingdom, phylum, class, order, family, genus, species. A broader (more inclusive) taxonomic level includes more diverse organisms. Among the options, kingdom is the broadest (e.g., Animalia kingdom includes all animals, which is more diverse than a phylum, class, or order within it).

Answer:

D. kingdom