how to deal with the questions?

The lecturer doubts that if we observe a difference between the marks, it might not be purely because of the difficulty of the assignment. As every student completed the assignments in the same order, there may be carry over effect or order effects present. It could be the case that students approached assignment 2 differently because of their feedback on assignment 1. This may mean our findings are showing the effect of this ordering, rather than the effect of a change in assignment difficulty. i. What is this phenomenon called in Statistics? [1 mark] ii. What can be done to avoid this issue