Amethod for assessing age-related changes that combines the cross-sectional and longitudinal approaches by observing a cross section of participants over a relatively limited period of time is called a . mixed longitudinal studyb. limited longitudinal studyc. longitudinal studyd. cohort study

a. mixed longitudinal study

True, by definition a mixed-longitudinal study is when "have defined some cohorts and these are followed for a shorter period and we can compare the precision, bias due to age and cohort effects" on the entire study. So that represent the perfect mix between longitudinal and cross sectional study.

Step-by-step explanation:

a. mixed longitudinal study

True, by definition a mixed-longitudinal study is when "have defined some cohorts and these are followed for a shorter period and we can compare the precision, bias due to age and cohort effects" on the entire study. So that represent the perfect mix between longitudinal and cross sectional study.

b. limited longitudinal study

This definition is not appropiate and is not usually used in the experimental designs.

c. longitudinal study

False, a longitudinal study is a design on which have "repeated observations of the same variables over short or long periods of time" and for this case we need cross sectional conditions, so for this case not applies.

d. cohort study

False, by definition a cohort study is an extesion of the longitudinal design but on this case " the samples are obtained from a cohort using cross-section intervals through time" and for this reason not applies for our case since we need a longitudinal design combined with the cross sectional design

astronomers is your final answer! : )