The Text Suggests That Older Adulthood Is Best Thought of as Consisting

Multiple Choice

The text suggests that older adulthood is best thought of as consisting of 4 distinct age-related periods. Why is older adulthood, but not other stages of development, divided into "substages"?

A) This is the fastest growing part of the U. S. population.
B) Older adults differ more dramatically from each other than do people in other age groups.
C) Older adults are mostly White, so they generally are not divided into racial/ethnic categories, making age the best way to divide them into groups.
D) Everyone in older adulthood is pretty much alike in most regards, so they need to be divided into different age groups so they can be studied more accurately.