Spread of disease is density dependent because it is more severe the greater the population density as the disease would spread more easily. If there is low population density it would spread slower.
Answer:
No, because some eukaryotic genes have introns that are not translated.
Answer:
Virus are a type of infectious agents it in almost all scenarios it will infect as many as cells it can before your WBC's can kill them
And in fact you are right now only in the state of Disease free. Every second your body is fighting off diseases. So to support your immune system eat Lots of Healthy food and stay safe!