Which of the Following Is/are TRUE of Schaie's Study of the Intellectual

Multiple Choice

Which of the following is/are TRUE of Schaie's study of the intellectual abilities of adulthood?

A) Schaie conducted both longitudinal and cross-sectional studies.
B) Schaie found that numerical ability and perceptual speed increased in middle age.
C) Schaie found that spatial orientation and verbal memory declined in middle age.
D) All of the above are true concerning Schaie's study.