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 several causes, some are more serious than others, but the most important cause could be melanoma of the nail called subungual melanoma. Nail discoloration that occurs as a vertical line is also called longitudinal melanonychia. It occurs due to an overproduction of melanocytes in that area of the nail. These streaks in fingernails are sometimes caused by ânail molesâ and similar to moles elsewhere in the body, may not develop into a more serious problem but still need to be monitored. Nail moles are more common in children.