The following are examples of nonmaterial culture except
a.
books.
c.
political systems.
b.
family patterns.
d.
work practices.

The correct answer is "A. BOOKS"

Non-material culture are the creations of human beings that are not incorporated in physical objects. They are, for example, norms, values, symbols, beliefs and language. The norms are the rules and expectations through which the society forms the guide of conduct of its members.

answer; i believe that the correct answer is ( rivers);

by using  production possibilities graph.  opportunity costs are key expenses in financial matters and are utilized as a part of registering money saving advantage investigation of a venture. such expenses, be that as it may, are not recorded in the record books but rather are perceived in basic leadership by processing the money costs and their subsequent benefit or misfortune.