Oddly, we don't really know why people bite their nails. Obviously before clippers were invented, teeth served the role in body maintenance, but excessive chomping is probably a comfort gesture, like thumb-sucking.
Its a Disease
no, its caused by injury to the matrix or an internal disease.
The atrophy or wasting away of the nail is called onychatrophia. This condition can result in thinning, deformity, or complete loss of the nail. It is often associated with underlying health conditions or trauma to the nail bed.
From research I have only determined the following; Onychatrophia can be caused by impact, damage or contact with chemicals, but if onychatrophia is found on most nails (finger nails and toe nails) it is usually caused by a more severe health problem. If this condition is accompanied by scabs or rashes across the body you must seek immediate medical attention as this is a sign of at least 3 deadly skin diseases. If your skin appears fine (not including the hard skin you probably are experiencing on your fingers as part of your onychatrophia) then it could be caused by a long time untreated thyroid problem or psoriasis.
The main cause to the start of the great depression was the Wall Street Crash in 1929.
Tourism is the 'main cause' of visits to Antarctica.
the main cause is that they run out of resources.
the main cause that die people in Africa is the hunger.
the main cause of bawku conflict is about land and a chieftance.
While enlightenment was a cause and the beheading.The MAIN reason was the taxes.
North moon is the main cause because
Global warming is a cause of the ozone depletion. However it is not the main cause of it.