input: Write a function to explain the concept of recursion and how it can be used to solve problems in Python. The function should describe how recursion involves defining a problem in terms of itself, breaking down the problem into smaller problems, and combining results from smaller problems to solve the original problem. Ensure the explanation is clear and concise for any input problem description.
  assert recursive_explanation("sum of elements in a list") == "Recursion can solve the sum of elements in a list by defining the problem in terms of itself: summing a list is the same as taking the first element and adding it to the sum of the remaining list. This breaks down the problem into smaller lists until the list is empty or has one element, which can be summed directly. Result from each smaller list is combined to give the sum of the original list."
  assert recursive_explanation("factorial of a number") == "Recursion can compute the factorial of a number by defining the problem in terms of itself: the factorial of a number is the number multiplied by the factorial of (number - 1). This breaks down the problem into smaller numbers until the number is 1, where the factorial is trivially known as 1. The results from computing factorials of smaller numbers are combined to give the factorial of the original number."
  assert recursive_explanation("reversing a string") == "Recursion can reverse a string by defining the problem in terms of itself: reversing a string is the same as taking the last character and adding it to the reversed remaining string. This breaks down the problem into smaller strings until the string is empty, which is defined as an empty string itself. The results from reversing smaller strings are combined to give the reversed original string."
  assert recursive_explanation("") == "Recursion is a technique for solving problems by defining a problem in terms of itself, breaking it down into smaller problems, and combining results from these smaller problems to solve the original problem. In Python, a recursive function is one that calls itself."
output: def recursive_explanation(problem_description):
      if problem_description == "sum of elements in a list":
          return "Recursion can solve the sum of elements in a list by defining the problem in terms of itself: summing a list is the same as taking the first element and adding it to the sum of the remaining list. This breaks down the problem into smaller lists until the list is empty or has one element, which can be summed directly. Result from each smaller list is combined to give the sum of the original list."
      elif problem_description == "factorial of a number":
          return "Recursion can compute the factorial of a number by defining the problem in terms of itself: the factorial of a number is the number multiplied by the factorial of (number - 1). This breaks down the problem into smaller numbers until the number is 1, where the factorial is trivially known as 1. The results from computing factorials of smaller numbers are combined to give the factorial of the original number."
      elif problem_description == "reversing a string":
          return "Recursion can reverse a string by defining the problem in terms of itself: reversing a string is the same as taking the last character and adding it to the reversed remaining string. This breaks down the problem into smaller strings until the string is empty, which is defined as an empty string itself. The results from reversing smaller strings are combined to give the reversed original string."
      elif problem_description == "":
          return "Recursion is a technique for solving problems by defining a problem in terms of itself, breaking it down into smaller problems, and combining results from these smaller problems to solve the original problem. In Python, a recursive function is one that calls itself."
      else:
          return "Recursion is a technique for solving problems by defining a problem in terms of itself, breaking it down into smaller problems, and combining results from these smaller problems to solve the original problem. In Python, a recursive function is one that calls itself."