Which of the following statements is true about procedures?

Procedures are a fundamental concept in programming that allows for code organization and reuse. The statement that procedures can share data among multiple parts of a program is true because procedures can either accept parameters that allow them to operate on different pieces of data or modify global variables that are accessible throughout the program. This sharing capability enhances code modularity and helps in managing complexity, as it allows different parts of the program to interact without needing to duplicate code.

The ability to share data is crucial for enabling varied functionalities, such as invoking a procedure with different inputs that can modify the state of a program or access shared resources. Each time a procedure is called, it can work with the most current values, which facilitates collaboration between different segments of the code.

Other statements do not hold up under scrutiny. Procedures can accept parameters, allowing them flexibility in functionality. They are not necessarily executed at the start of the program, as they can be called at any point during execution. Additionally, procedures are not limited to returning a single value; they can return multiple values or even operate without returning anything at all, depending on their design and purpose.