Respuesta :
They have similar or common ancestor. The similarities inherited from the common ancestor as in the case of homologous organs. In evolutionary biology a group of organisms share a common descent if they have a common ancestor. There are many other examples like in the case of hemoglobin to prove the theory of common ancestor
The close similarities between the make-up of the oxygen-carrying molecule hemoglobin in organisms is due to Common ancestor.
What are common ancestors?
Common ancestor is is a set of organism is the most recent individual from which all the organisms of the set are descended.
The physical features which are shared by different organism due to evolutionary history are known as homologous. All organism on the earth will have a single common ancestor and they show similarities like birds, horses, gorillas, and humans.
Hence, the factor is common ancestors.
To know more about common ancestors, visit the below link:
https://brainly.com/question/1234951