Python functions are reusable blocks of code that perform specific tasks. Functions make code more modular and easier to read and maintain, as developers can divide complex tasks into smaller, more manageable sub-tasks. Python supports both built-in functions, such as print() and len(), and user-defined functions, which can be defined by the developer to suit their specific needs.

In Python, variables have different scopes, which determine where they can be accessed from within a program. Global variables can be accessed from anywhere in the program, while local variables are only accessible within the function in which they are defined. Understanding variable scopes is crucial for writing well-organized and efficient Python code, as it helps prevent naming conflicts and optimize memory usage. By mastering Python functions and scopes, developers can write more efficient, organized, and reusable code.