Final answer:
Human embryos exhibit gill slits and a tail during early development which link them to a common ancestor with fish and reptiles; these features develop into different structures in humans, such as parts of the lower jaw, inner ear, and the coccyx.
Step-by-step explanation:
The traits in human embryos that link them to a common ancestor with fish and reptiles are the gill slits and tail. During human embryonic development, pharyngeal slits appear which are homologous to fish gills but develop into different structures in humans, such as parts of the lower jaw and the bones of the inner ear.
Another shared embryonic feature is the tail, which in humans develops into the coccyx, or tailbone. The presence of these features during early development provides evidence of evolutionary history and common ancestry among vertebrates.