What is the primary reason that the young-old are more likely to be better educated and have higher levels of wealth than the old-old and the oldest old?
a. The young-old grew up in favorable economic times.
b. The young-old grew up with social norms that emphasized independence and hard work.
c. The young-old have better healthcare and nutrition.
d. The young-old are more politically active.
e. The young-old are more entrepreneurial.