Philosophical: Which geo mobility is more important? That of a) products, of b) capital or that of c) humans?
Pollution, weather, birds, viruses, etc know no borders! Capital and products almost none. Then why should humans?
Which factors promote mobility of people within the USA? a) mentality b) single language c) other(s) (which)?
On the other hand: Which factors prevent mobility of people within the EU? a) Conformism b) languages c) red tape (tax and social security) d) other (which)?
Global free immigration and mobility: if we do not institute (and promote it?) it now, the effects of global warming will, in a few decades