In phylogenetics, what best describes a derived trait and its role in identifying clades?

In phylogenetics, what best describes a derived trait and its role in identifying clades?

• A. A trait present in the ancestor that defines a monophyletic group
• B. A trait that is unique to a single lineage with no relation to others
• C. A trait caused by environmental factors only
• D. A trait that evolved in a lineage from the last common ancestor

Answer: (D)