Final answer:
When the end of a function block is reached during execution, the function returns control to the calling part of the program, often with a return value. In some cases, it may return undefined or a default value if no explicit return statement is present.
Step-by-step explanation:
When a function is executing in a programming context, reaching the end of the function block typically signifies that the function has completed its tasks. At this point, the function will return control back to the part of the program where it was called.
This is usually accompanied by returning a value that can be used further in the program's execution. However, a function may also end without returning a value, which is often the case in functions that perform an action without calculating a result.
Depending on the programming language, reaching the end of a function without an explicit return statement may return a default value or undefined.