Explain the concept of base case and recursive case in recursion.

Recursion is a method of solving problems in computer science where a function calls itself as a subroutine. This allows the function to be written in a much simpler form, and can also solve complex tasks. However, for a recursive function to stop calling itself, we need to impose a condition. This is where the concept of base case and recursive case comes in.

1. Base Case: The base case is a condition in a recursive function that does not lead to further recursive calls. It's a scenario where a problem can be solved without further recursion. A recursion can lead to an infinite number of function calls, so a base case helps to stop the recursion from going on forever. For example, if we are writing a recursive function for calculating the factorial of a number, the base case would be if the number is 0 or 1, return 1.

2. Recursive Case: The recursive case is a condition in which the function calls itself with a new argument, aiming to bring it closer to the base case. It breaks down complex problems into simpler ones. For example, in the factorial function, the recursive case would be if the number is not 0 or 1, return the number multiplied by the factorial of the number minus one.

In summary, the base case and recursive case are essential components of a recursive function. The base case provides a condition that stops the recursion, while the recursive case breaks down the problem into simpler, more manageable parts.