Effects are a major problem found in cross-sectional research.

Lack of reproducibility and accuracy effects are a major problem found in cross sectional research.

Explanation:

Cross sectional research is a kind of research where the characteristics of a particular group of population at a particular time has been studied on some situation.

This research is based on the situation in which the population is placed and also on perspective of each item in the population. There is biasing problem in analyzing and concluding the results obtained from cross sectional research.

Also it is not sure that different group will show same characteristics in same situation or condition , thus accuracy in analyses and reproducibility of analysis are the major effects which causes problem in cross sectional research.

i don't know the answer to this

sounds good to me mate!