In Guns, Germs, and Steel, what man-made constructions allowed for increase in human population density in Hawaii?guns germs steel

When answering this question, you must think about
"man-made constructions" in a broader sense.  You must think of it in terms of societal
and governmental "constructions," not simply in terms of physcial things.  The
"construction" that allowed for an increase in population density was, to Diamond, the
organized chiefdom.

Diamond argues that the presence of an
organized, hierarchical government makes it easier to have intense use of natural
resources.  Hawaiian chiefs were able to make their subjects take part in "public works"
projects like creating irrigation systems.  These works made it more possible to do
intense agriculture and thus to have a higher population
density.

The more organized a society, the more it is able
to feed a large number of people and cause them to get along peacefully together.  This
organized society was the important "construction" in Hawaii.