who came first hen or egg
This is one of the questions from the list of unsolved questions. Some scientists favour that the egg came first and many favour that the hen came first.
This question is slightly ambiguous because it is not clear whether the question speaks about the egg or the hen's egg. If we check the question in its present sense then we can conclude that the egg came first. The conclusion can be supported by the fact that with respect to the evolution the egg laying capacity was there even in invertebrates and the hens came into existence after a very long time.
Hope this answers your query.