What role does the use of backticks play in PHP code execution?

Using backticks in PHP allows you to execute shell commands directly from your PHP code. This can be useful for tasks such as running system commands, interacting with the server's operating system, or executing external programs. However, it is important to use backticks carefully, as they can pose security risks if user input is not properly sanitized.

$output = `ls -la`;
echo $output;