Final answer:
Comparative embryology supports evolution by showing embryonic similarities like gill slits and tails in different species, suggesting a common ancestry. These similarities indicate inherited genes from shared ancestors rather than direct descent from modern fish or recapitulation of evolutionary history during development.
Step-by-step explanation:
Comparative embryology provides significant evidence for evolution similar physical characteristics seen in the embryos of different species. The presence of gill slits and tails in the embryos of both chickens and humans, which are traits absent in the adult forms of terrestrial vertebrates, supports the idea of a shared ancestry. It demonstrates how certain genetic features, coded by ancestral genes, manifest in the embryonic development phase before diverging in the adult forms of different species.
The correct answer to the given question is that the similarities between chicken and human embryos suggest that chickens and humans descend from common ancestors with genes that code for the development of tails and gill slits. This indicates that these species, despite their differences as adults, have inherited these embryonic development traits from a common ancestor, pointing to an evolutionary relationship between them.
It is crucial to note that the comparison of embryos is not used to suggest that modern vertebrates go through the adult stages of their evolutionary history during development, nor that they are direct descendants of modern fish. Instead, embryonic similarities echo the historical, genetic, and evolutionary connections between species.