What does life expectancy measure? the average income a population likely earns during employment
the average human development during a population’s lifetime
the average number of years that a population is likely to live
the average standard of living during a population’s lifetime

the average number of years that a population is likely to live

Explanation:

Life Expectancy is usually counted in order to find out a general idea on the standard of living in a country.

It's a measurement that can be examined to find out how the country is dealing with issues like : Medical care for it's citizens, service distribution among people with different income level, quality of their foods & water, the advancement in their medical knowledge, etc.

Typically, countries with higher GDP per capita will have higher expectancy compared to developing countries.

the united states has a federal government. the president is the head of the federal government of the united states. however, each state forms its government for administration purposes. the powers of the state governments are exercised within restricted state boundaries. and citizens participate in this government by voting.