Public health emergencies are increasing worldwide. When there are more people, there is an increase in susceptibility (i.e., more people = more susceptibility). A broader, more extensive framework is necessary to protect communities from public health emergencies.

Please answer the following questions:

What is the role of public health in times of Population Crises and Emergencies? 
How does the National Response Framework relate to the role of public health? 
How does the Incident Command System improve emergency response?

should be supported by at least two references.