What does the term 'class' refer to in biological taxonomy?

In biological taxonomy, the term 'class' refers to a group made up of several orders. This level of classification is hierarchical, with different taxonomic ranks including domain, kingdom, phylum, class, order, family, genus, and species. The class is a significant rank in this hierarchy, representing a higher level of organization than orders but a lower level than phyla, which are made up of one or more classes.

For instance, in the classification of mammals, the class is 'Mammalia,' which encompasses multiple orders such as Carnivora (carnivores), Primates (primates), and Rodentia (rodents), among others. This structural organization helps biologists and researchers categorize and understand the diversity and evolutionary relationships among living organisms based on shared characteristics and evolutionary history.

The other options incorrectly define the scope or meaning of 'class' in taxonomy, as they either refer to smaller taxonomic units (such as species or families) or emphasize environmental factors, which do not fit within the classification hierarchy itself.