Diseases tract infection

Classify respiratory tract diseases, their causes, and the pattern of associated symptoms.
How are infections of upper respiratory tract different from those of lower respiratory tract?
Why are infections of the upper respiratory tract milder as compared to those pertaining to the lower respiratory tract?
Describe the curative methods for each of upper and lower respiratory tract infection.
What are three specific factors that help clearing the lower lung of infectious agents?

Additional Requirements 

Other Requirements: 
Classify respiratory tract diseases, their causes, and the pattern of associated symptoms.
How are infections of upper respiratory tract different from those of lower respiratory tract?
Why are infections of the upper respiratory tract milder as compared to those pertaining to the lower respiratory tract?
Describe the curative methods for each of upper and lower respiratory tract infections.
What are three specific factors that help clearing the lower lung of infectious agents?