Which of the following best describes the role of comments in code?

Comments in code are primarily used to provide explanations or clarifications for the code itself. They allow developers to annotate their code with notes that explain the purpose or logic behind specific sections. This can be invaluable for anyone reading the code, including the original author when they return to it after some time, as well as other developers who may work on the project in the future.

By including comments, developers can make their code more understandable and maintainable. Comments can describe what a particular block of code does, the rationale behind certain decisions, or any important information that could assist in debugging or future updates. This practice ultimately leads to better collaboration and communication within a development team.

The other options do not accurately reflect the function of comments in coding. Comments do not execute hidden functions, nor do they define variables and functions or influence the speed at which code runs. Their sole purpose is to enhance readability and comprehension for human readers, not to affect the program's functionality directly.