Nations usually industries and activities in which they have a comparative advantage over other nations.
a. negotiate treaties for
b. specialize in
c. avoid
d. give the government control over
user: nations usually industries and activities in which they have a comparative advantage over other nations.
a. negotiate treaties for
b. specialize in
c. avoid
d. give the government control over

b. specialize in.

Explanation:

When is about production and national economy, Nations most of the time specialize in industries which are advantageous for them. For example, if the country is rich in oil, they will specialize in oil, if the country is rich in silver, they will specialize around it. This is an strategy to ensure a economical stability in the country. Imagine that a Nation specialize in copper, which its main source is from another country, they will depend on them always, because they don't have copper mines at all.

The business cycle is the periodic but irregular up-and-down movement in economic activity, measured by fluctuations in real gross domestic product (gdp) and other macroeconomic variables. a business cycle is typically characterized by four phases—recession, recovery, growth, and decline—that repeat themselves over time. economists note, however, that complete business cycles vary in length. the duration of business cycles can be anywhere from about two to twelve years, with most cycles averaging six years in length. some business analysts use the business cycle model and terminology to study and explain fluctuations in business inventory and other individual elements of corporate operations. but the term "business cycle" is still primarily associated with larger (industry-wide, regional, national, or even international) business trends.