virulence factors of Giardia Presentation.pptx Study design is a specific plan or protocol for the study, which allows to translate into an operational one. Three famous writers (William Shakespeare ) (Agatha Christie ) (Ahmed Shawqi) Coronaviruses are a large family of respiratory viruses that includes COVID-19 Tinea versicolor (Pityriasis versicolor, is a common fungal infection of the skin)