Whats the elements of world cultures

How does specialization enable countries to trade with one another? a country can make and sell goods affordably and buy goods that it is inefficient at making. a country can make what it chooses and sell its goods to other countries. a country can decide to buy everything it needs from other countries. a country can efficiently make goods that were once difficult to make.

The procedures for reporting potential unanticipated problems involving risk to subjects or others to the irb are: stated in the human subject protection regulations, but not in the drug or device regulationsincluded in the consent processdetermined by research staffdetermined by the institution in its written policies and procedures

When recursive formula can be used to determine the total amount of money earned in any year based on the amount earned in the previous years?