The characteristic is found among all members of the clade, which makes it shared. It is not present among the ancestors of the clade, but was derived from the last common ancestor and is unique to that clade. These attributes make the trait a shared derived character.

An example of a shared derived character is hair in mammals: all mammals have hair, but no ancestors of mammals (that are not mammals themselves) had hair.

An example of a shared ancestral character is backbones in mammals: all mammals have backbones, and so do other vertebrates. There was a common ancestor between mammals and other vertebrates that had a backbone; however, when comparing all vertebrates to invertebrates, a backbone becomes a shared derived character, as backbones are unique to vertebrates.

A clade is a group of related species all descending from a common ancestor, including that ancestor. They have at least one shared derived trait unique to the clade and differentiating them from all other clades. Clades can be nested within each other: the mammalian clade is part of the vertebrate clade, which is part of the animal clade.

In the system of biological classification, organisms are classified in a hierarchy, or taxonomy. The highest levels of classification are the most inclusive, while the lower levels become more and more specific until a single species is identified. From most inclusive to least inclusive, organisms are assigned a kingdom, a phylum, a class, an order, a family, a genus, and finally a species.

Organisms sharing the same classification at less inclusive levels will be more closely related. For example, two organisms sharing the same genus will be more closely related than those who only share the same family. Of the given answer choices, family is the most specific level of classification.

Punctuated equilibrium is one theory within evolutionary biology that seeks to explain the rate of evolution over time. This theory describes most species being in a state of stasis, with little change occurring. When change does occur, however, it is rapid. The theory of punctuated equilibrium stands in opposition to the theory of gradualism and is supported by the fossil record.

Gradualism is a theory of evolutionary biology that stands in contrast to the theory of punctuated equilibrium. In this theory, change (or evolution) is slow, gradual, and uniform. Adaptation occurs over a long period of time and is observed in small changes. 

Phylogenetics is the study of relationships between organisms and groups of organisms. This is done through the production of phylogenetic trees, which are used to describe these relationships. To make phylogenetic trees, scientists use molecular sequencing and/or morphological similarities in order to characterize the relationships between organisms.

Phylogenetics has several difficulties that complicate the development of accurate phylogenetic trees. Relationships between organisms on a genetic level are incredibly complicated, making it difficult for scientist to create clean and precise phylogenetic trees. These difficulties include hybridization, horizontal gene transfer, and convergent evolution.

There are 3 domains in which all organisms are classified - Eukarya, Bacteria, and Archaea. Fungi is the name of one the kingdom classifications. The order for the classification is as follows: domain, kingdom, phylum, class, order, family, genus, species. Therefore, Fungi falls under the Domain of Eukarya.