20. A variable is one defined inside a function's body 21. A been defined yet. __tells the compiler that a function exists but may not have 22. If a function doesn't return a value, type. ade, - appears as the returned 23. Using the function. means that a copy of the argument is made when calling 24. Using means that the function is sharing the calling routine's memory for the argument 25. Before you can call a function it must be or