What research method is used in order to establish what causes a behavior? an experiment What is the first step of the scientific method? pose a question In the science of human development, &quot;nurture&quot; refers to: environmental influences.
Vertical lines on one's nails, like those the writer seems to have, are a common phenomenon that often get more pronounced with age. There are many reasons for ridged nails but the most common is aging, says Dr. Phoebe Rich, M.D., FAAD, clinical adjunct professor of dermatology at Oregon Health Science University.
There are many causes of grooves or ridges on fingernails. Vertical grooves or ridges are quite common; however, horizontal ridges are not and they may signify an underlying illness. Consult your doctor should you discover horizontal ridges on your fingernails.