Question

over the past 170 years in the united states, life expectancy
a. has remained fairly constant.
b. has slightly declined.
c. increased up to the 1950s and then declined for the next 60 years.
d. has almost doubled.

Explanation:

Life expectancy in the United States has increased significantly over the past 170 years due to advancements in medicine, public health, and living standards. It has not remained constant (A is wrong), declined slightly (B is wrong), or increased - then - declined (C is wrong).

Answer:

D. has almost doubled.