What feature in the embryonic stage of vertebrates was used to support the idea of evolution?
What feature in the embryonic stage of vertebrates was used to support the idea of evolution?
A row of vestigial gill slits
A tail
A notochord
A heart
Solution
Heckel used the observation that the embryos of all vertebrates, including humans, develop a row of vestigial gill slits just behind the head, but it is a functional organ only in fish and not found in any other adult vertebrates as evidence for the evolution of vertebrates.