Recursion involves functions that call themselves, which can be useful for solving problems that can be broken down into smaller, similar subproblems. A key aspect of recursion is establishing a terminating condition to prevent infinite loops, typically implemented using an if-else statement. For example, the factorial function demonstrates recursion: it defines factorial(1) as 1 and factorial(n) as factorial(n-1) multiplied by n for n greater than 1. The factorial function can be coded recursively in C, but it can also be converted to an iterative version using a loop. However, certain problems, especially those involving mutually recursive functions like expression parsing, may be more complex and better suited for recursive solutions.