If a country had 4 million people in 2000 and 3.5 million people in 2010, which
of the following factors must have contributed to the population change?
o
a. a decrease in the crude death rate
b. an increase in the crude birthrate
o
c. an increase in the average lifespan
d. an increase in the infant mortality rate

Option C, An increase in average lifespan

Explanation:

The decrease in the population of humans is attributed to events like long-term population trends such as reproduction under replacement, urban decay, crime, disease or other disasters in a population of humans.  

A decrease is caused by migration in human populations.

The average lifespan in the USA has dropped for the second time in 3 years, as shown by three recent CDC studies. drug overdose deaths and self killing caused much of the downturn, with even more than 70,000 reported deaths in 2017.

answer; the period of time known as the middle ages;

after world war ii, the united states and the soviet union were the major economic, military, and political powers. the world was bilateral multipolar bipolar unilateral

after world war ii, the united states and the soviet union were the major economic, military, and political powers. the world was bipolar.  

the great leap forward, mao zedong's plan to increase china's agricultural and industrial production, was an overwhelming success. true false

the great leap forward, mao zedong's plan to increase china's agricultural and industrial production, was an overwhelming success. true.

explanation: