Dialectic materialism figures out, intrinsic factor is the basic reason causing evolvement, while external factor is the condition.
a chronic progressive anemia of older adults; thought to result from a lack of intrinsic factor (a substance secreted by the stomach that is responsible for the absorption of vitamin B-12).
Parietal cells generate stomach acid as well as a substance called intrinsic factor, which enables a vitamin called B12 to be absorbed further along in the gut.