Can a p-value be greater than 1? Why or why not?
No, a p-value cannot be higher than one.
A p-value tells you the probability of having a result that is equal to or greater than the result you achieved under your specific hypothesis.
It is a probability and, as a probability, it ranges from 0-1.0 and cannot exceed one. A p-value higher than one would mean a probability greater than 100% and this can't occur.