With Best Regards: Closing Your Letter. June 17, 2014 by. When writing professional or informal emails and letters, it is often considered proper etiquette to complete your correspondence with an appropriate closing signature.
What two conditions are needed for clouds to form? Air must be cooled to its dew point and particles must be present in the air When are clouds formed by ice crystals instead of drops of liquid water?
The creation of lightning is a complicated process. We generally know what conditions are needed to produce lightning, but there is still debate about exactly how a cloud builds up electrical charges, and how lightning forms.