"The combination of a brick red belly and grey back seen in the American Robin, Turdus migratorius, are not seen in closely related species in the genus Turdus. Which term best describes these features of the American Robin relative to these other species?

a. Synapomorphy
b. Autapomorphy
c. Apomorphy
d. Symplesiomorphy
e. Shared derived character

The best term that portrays the highlights of an american robin with its nearby family members is autapomorphy.  

An autapomorphy is a particular component that is remarkable to a given taxon. In the given case, this component is block red gut and dark back. This component is seen in just the american robin species and not related species in the family.  

Apomorphy is characterizes as a novel trans-formative attribute that is one of a kind to a specific animal categories and every one of its relatives and which can be utilized as a characterizing character for an animal groups or gathering in phylogenetic terms. For instance ownership of quills is an element one of a kind to flying creatures and is a characteristic that characterizes all the individuals from the Ave's class.  

Synapomorphy is a trademark present in a tribal species and shared solely by its trans-formative relatives.  

A plesiomorphy or symplesiomorphy is a tribal character or attribute state shared by at least two taxa.

doctors i believe if i'm wrong sorry

that is wrong, its not thymus.