Biologists studying a clade of birds are interested in determining whether a morphological feature specific to this clade is ancestral or derived. Which of the following approaches would best address this question?
Analysis of bird embryos to determine the developmental stage at which the trait emerges
Amino acid sequencing of proteins relevant to the morphological feature in the living birds
More detailed morphological analysis of living bird tissue using an electron microscope
Morphological analysis of fossilized organisms closely related to the birds' common ancestor
DNA sequencing of the genes responsible for the trait
Morphological analysis of fossilized organisms closely related to the birds' common ancestor
