$questions = simplexml_load_file("../XML/questions.xml");

$local = 0;
if($local == 0){
    $server ="localhost";
    $user = "root";
    $pass = "";
    $db = "quiz";
}
$konektatu = mysqli_connect($server, $user, $pass, $db);

$sql = "INSERT INTO questions VALUES('','$_POST[posta]', '$_POST[galdera]', '$_POST[zuzena]', '$_POST[okerra1]','$_POST[okerra2]','$_POST[okerra3]', '$_POST[zailtasuna]', '$_POST[arloa]')";

$question = $questions->assessmentItem[0]->addChild('assessmentItem');
$question->addChild('itemBody','Hau galdera izango zen');
$question->addChild('correctResponse','Hemen erantzun zuzena');
$question->addChild('incorrectResponses','Hemen erantzun okerra' . 'Hemen Bigarrena');

$execute=mysqli_query($konektatu,$sql);
if(!$execute){
    echo"Ezin izan dira datuak txertatu. ".mysqli_error($konektatu);
}else{
    echo"Datuak txertatu egin dira";
    echo"<a href=../HTML5/showQuestions.php> Ikusi Datuak </a><br>";
    echo'<a href=../PHP/showXMLQuestions.php>Ikusi Datuak (XML) </a>';
}
mysqli_close($konektatu);

<?xml version="1.0"   encoding="UTF-8"  ?>
<assessmentItems>

    <assessmentItem complexity="3" subject="mikologia">

        <itemBody>

            <p>Zein Amanita da jangarria?</p>

        </itemBody>

        <correctResponse>

            <value>Caesarea</value>

        </correctResponse>

        <incorrectResponses>

            <value>Phalloides</value>

            <value>Muscaria</value>

            <value>Virosa</value>

        </incorrectResponses>

    </assessmentItem>

    <assessmentItem complexity="3" subject="mikologia">

        <itemBody>

            <p>Tripakiek zer dute kapela azpian?</p>

        </itemBody>

        <correctResponse>

            <value>Eztenak</value>

        </correctResponse>

        <incorrectResponses>

            <value>Filamenduak</value>

            <value>Himenioa</value>

            <value>Hodiak</value>

        </incorrectResponses>

    </assessmentItem>

    <assessmentItem complexity="5" subject="mikologia">

        <itemBody>

            <p>Eranztuna du</p>

        </itemBody>

        <correctResponse>

            <value>Galanpernak</value>

        </correctResponse>

        <incorrectResponses>

            <value>Gibel urdinak</value>

            <value>Esnegorriak</value>

            <value>Errotariak</value>

        </incorrectResponses>

    </assessmentItem>

</assessmentItems>