In: Psychology
Crosssection research is done to find out a comparison between two different samples at a particular point in time. The longitudinal study is an in-depth study of long phases of change that might occur in humans/living beings/social conditions, etc over a longer period of time.
The sample is different in crossectional research. One same sample is used in longitudinal research. The change is found at the societal level [cross-sectional] whereas change is found at the individual level [longitudnal]
longitudinal would be more appropriate as it talks about changes in a sample over a long period of time. These changes are caused by certain variables or different variables that the sample gets introduced to. For instance, The development of babies in different cultures. There are various biological and social factors that are affecting the baby's development over different times. Cross-cultural study will focus on the how one group is different with another on particular variable.