Answer 1

A statement is a single logical expression, like variable assignment (a = 6), conditional statement (if a == 6:) and other special-purpose: pass, return, del, etc.

A function - or more often called - a method, is bound to classes and objects - it defines a way objects behave and are dealt when the method is called. For example, __init__ method is called each time an object of a class is created, __add__ is called when you try to add two objects with a "+" operator, and so on.