Final answer:
b) a homologous trait that is shared among certain species. A synapomorphy is a homologous trait that is shared among certain species. It is a characteristic that evolved in a common ancestor and was inherited by all of its descendants. It is used to determine the relationships and identify monophyletic groups in phylogenetic trees.
Step-by-step explanation:
A synapomorphy is a homologous trait that is shared among certain species. It is a characteristic that evolved in a common ancestor and was inherited by all of its descendants. It is used to determine the relationships and identify monophyletic groups in phylogenetic trees. For example, in the evolutionary history of primates, opposable thumbs are a synapomorphy that is shared by humans and their common ancestors.
A synapomorphy is a homologous trait that is shared among certain species and their common ancestor. It is a derived trait, meaning it evolved in the lineage leading to a clade (a group of organisms that includes an ancestor and all of its descendants) and is present in all members of that clade. Synapomorphies are important in phylogenetics (the study of evolutionary relationships) as they help identify and define clades, contributing to the construction of phylogenetic trees.