What is the role of the `if` statement in Python?

The if statement in Python is crucial for controlling the flow of a program based on specific conditions. It allows programmers to execute a block of code only when a certain Boolean expression evaluates to true. This conditional execution is fundamental for implementing decision-making logic within the code. For instance, you can use an if statement to check if a variable meets a particular criteria and only run some code if that condition is satisfied.

Using the if statement enhances code flexibility, enabling different outcomes based on varying inputs or states. By structuring your program with if statements, you can create more dynamic and responsive applications that behave differently under different circumstances.

The other options do not accurately describe the function of the if statement. Unconditional execution is handled by other constructs, function definition is governed by the def keyword, and loops are created using constructs like for or while.