Recurrent aphthous stomatitis (RAS) is an inflammatory condition of oral mucosa and is very common that occur in 20% of population. in which 80% of all cases are minor type. Etiology remains unknown but there are factors that can precipitate the attack. known as predisposing factors. https://echobookmarks.com/story19493231/application-of-qvp-method-to-winter-precipitation-observation-based-on-polarimetric-radar