What is the difference between iteration and recursion?

• A. Iteration is step by step
• B. Recursion involves a function calling itself
• C. Both are identical in approach
• D. Iteration uses memory more efficiently than recursion

Answer: (A)

The main idea is how repetition is achieved. In recursion, a function calls itself with smaller subproblems and stops when it hits a base case; each call waits for the next to finish, building up a stack of calls until it returns. In iteration, you repeat a block of code with a loop (for or while) without adding new function calls to the stack. Because recursion relies on the call stack, it can use more memory and risk stack overflow for deep problems, whereas iteration is typically more memory-efficient and straightforward for repeating work. The notion that iteration is simply “step by step” describes a way to execute, but it doesn’t capture the essential mechanism difference—recursion hinges on self-calling with a base case, while iteration relies on loops.