What are the base case and recursive case? What is their role in a recursive program?

Q. What are the base case and recursive case? What is their role in a recursive program?

Answer =

In a recursive solution, the base cases are predetermined solutions for the simplest version of the problem:
if the given problem is a base case, no further computation is necessary to get the result.

The recursive case is the one that calls the function again with a new set of values. The recursive step is a set of rules that eventually reduces all versions of the problem to one of the base cases when applied repeatedly.