The correct options are: "improved medicine and sanitation - an increase in the average life expectancy"
Since the mid-twentieth century, that is, since 1950, the world population has continued with high population growth, even with low birth rates in many countries, since the strong and constant reduction in mortality has been linked the generalized increase in life expectancy. Thus, in 2000 it reached 6,000 million inhabitants in the world, 7,000 million in October 2011 and 7,200 million in October 2013. From the year 2000 to October 2013 the population has continued to increase significantly, in the order of 92 million more per year.
