Answer to Question 1
The flu doesn't meet an important criterion associated with successful use of the N of 1 RCT. The flue is neither stable nor chronic; it can't be evaluated over time because it doesn't last long enough. A group design would be better because a researcher can evaluate different treatments over the relatively short course of the flu, without worrying that the symptoms would disappear before different treatments could be evaluated.
Answer to Question 2
A qualitative independent variable is one for which the various levels or conditions differ by category; the differences across group isn't one of more or less. On the other hand, a quantitative independent variable differs along a continuum, so you can say that one condition involves more or less of something.
Studying the Axon
Rice noodles are a good gluten-free substitute for pasta
Oatmeal and other whole grain cereals are good sources of carbohydrates to start your morning off
Nuts are also a good source of dietary fibre
The first successful gene therapy trial