Geographic variation was the study or examination that living things which are relatively similar are different because of their habitat and geography was dissimilar. Comparable organisms parted ways by physical features and global positioning.
It depends on the position of the species a cline can happen. This can relate to a specific one of two or more substitute forms of a genetic factor that arise by transformation and are found at the same place on a chromosome which will assist in surviving of a different but reachable geographic location.
