Complex sentence: Onychophagia or nail biting is a common oral compulsive habit in children and adults.In children it is caused by feeling of insecurity, conflict and hostility.it may be due to pressurrised study at school or due to watching violent scenes.
Split into simpler sentences: Onychophagia or nail biting is a common oral compulsive habit in children and adults. It may be due to pressurrised study at school or due to watching violent scenes.