According to the author of Guns, Germs, and Steel, which is not an area very suitable for food production?

In
,is not particularly
interested in parts of the world that are not suitable
for food production. 
For Diamond, places that are never going to be suitable for farming are
not
terribly important.  Diamond does discuss such areas, for example, at the beginning
of
Chapter 5.  There, Diamond tells us that there are large areas of the
globe where ecological
reasons make food production difficult or impossible
even today.  There are some places, like
the Arctic or deserts, that are
completely unsuitable for food production.

However, these
types of places are not particularly...