What programming structure executes additional commands when a condition is false?

The correct answer is that the "if / then / else" structure executes additional commands when a condition is false. This programming structure is designed to evaluate a specified condition. If the condition evaluates to true, the commands within the "if" block are executed. Conversely, if the condition is false, the commands within the "else" block are executed.

This conditional logic allows developers to implement decision-making capabilities within their programs, making it possible to handle different scenarios based on the evaluation of conditions. The "if / then / else" structure is fundamental in programming as it enables the execution of specific code paths depending on varying circumstances.

Other options such as loops, switch cases, and function declarations serve different purposes. For instance, a for loop is iterative and is used to repeat a block of code a specific number of times, while a switch case is typically used to select one of many blocks of code to execute based on the value of a variable. A function declaration defines a reusable code block but does not inherently evaluate conditions. Therefore, the "if / then / else" structure is uniquely suited for executing additional commands when a condition is false.