Most of the Difference in Life Expectancy in the United

Most of the difference in life expectancy in the United States now compared with that 100 years ago is accounted for by:

A) better chances that young people will live to adulthood
B) better chances that middle-age people will live to old age
C) better chances that old people will live to be 100 years old
D) greater dangers now than then, primarily because of higher crime rates
E) higher mortality rates now due to war and terrorism