Answer: If one is constructing a phylogeny of reptiles using DNA sequence data of birds, mammals, amphibians or fish, the suitable outgroup to be used are mammals due to the time of divergence from other group of organisms.
Explanation: Phylogeny is used to determine evolutionary relationship between items or organisms. A phylogenetic tree is a graphical illustration of phylogenetic relationship. In phylogeny, an outgroup represent an organism that is more distantly related to other group of organisms.
In a phylogenetic tree, outgroup stands alone. It shows that the time of divergence of that particular organism is far from other group of organisms. Outgroup is used to root a tree and sometimes represent a group that is more ancestral on a tree.
It should be noted that differences in the DNA sequences of the organisms under consideration will determine which organism will serve as the outgroup.
In the science world today, both the natural regeneration and stem cell therapy can be used to generate new cells and both processes have thier advantages and disadvantages. The following are the advantages of natural regeneration over stem cell transplants:
1. Natural regeneration is cheaper compares to stem cell transplant.
2. The process of natural regeneration is safe and does not involve the fear of unknown, long time effects like that of stem cell transplant.
3. Naturally regenerated cells can not be rejected by the patient's body but a stem cell transplanted cell can be rejected by the patient's body.
