Passing a PHP value to a page and back - php

Question

Although sending the form to the receiving page works normally (via $_POST), I'd like to know how it can be sent back through an <a> tag. Is it possible without the use of AJAX or any JS scripts? I'm thinking about using cookies but have no idea on how to set it in-between the PHP/HTML scripts.
Here's a code sample for what I'm doing
Question page:
<form action="results.php" method="POST">
<select name="SampleSelect">
<option>Sample1</option>
<option>Sample2</option>
<option>Sample3</option>
</select>
</form>
Answer page:
Return to questions
<?php
$answer = $_POST['SampleSelect'];
echo $answer;
?>

Answer 1

This could be achieved with sessions
Start or resume a session with session_start() and then store the answer in the session. The code could look like this:
answer.php:
<?php
session_start();
?>
Return to questions
<?php
$answer = $_POST['SampleSelect'];
$_SESSION['answer'] = $answer;
echo $answer;
?>
question.php:
<?php
session_start();
$answer = $_SESSION['answer'];
$options = [
"Sample1",
"Sample2",
"Sample3"
];
?>
<form action="results.php" method="POST">
<select name="SampleSelect">
<?php
foreach ($options as $option) {
if ($option === $answer) {
echo '<option selected>' . $option . "</option>\n";
} else {
echo '<option>' . $answer . "</option>\n";
}
}
?>
</select>
</form>

Answer 2

Yes, you can pass it as a $_GET
$var = 'something';
echo "<a href='questions.php?var=$var'>Pass me back</a>";
In your questions PHP file you'll grab it:
$var = $_GET['var'];
echo $var;