How do you define a function in Python?

Defining a function in Python is done using the "def" keyword followed by the function name and a pair of parentheses. This syntax sets the stage for creating a reusable block of code that can take input parameters (if any are specified within the parentheses) and can optionally return a value. The structure is crucial as it informs the Python interpreter that what follows is a function definition.

The components include:

• def: This keyword signifies that a new function is being defined.

• Function name: This is the identifier used to call the function later in the code.

• Parentheses: These are used to enclose any parameters the function may accept; they are mandatory even if there are no parameters.

For instance:

def my_function():

print("Hello, World!")

In this example, "my_function" is defined to print a message when called.

The other options suggest incorrect keywords or phrases that do not align with Python's syntax for function definition. They either use non-existent keywords or do not follow the required format, thus making them invalid choices for defining a function within Python.