Which of the following describes a major limitation of cross-sectional research? Multiple Choice In a cross-sectional study that compares IQ scores, the difference in IQ scores of 25-year-olds and 45-year-olds is due to the 45-year-olds having taken the same test at several points in time. In a cross-sectional study that compares IQ scores, the difference in IQ scores of 25-year-olds and 45-year-olds is due to differences in their life experiences. In a cross-sectional study, the participants may move or die before the study has been completed. In a cross-sectional study, the researchers incur significant expenditure of time as he or she waits for the participants to get older.