protected function marshall(QtiComponent $component)
    {
        $element = $this->createElement($component);
        $this->fillElement($element, $component);
        $this->setDOMElementAttribute($element, 'responseIdentifier', $component->getResponseIdentifier());
        $this->setDOMElementAttribute($element, 'title', $component->getTitle());

        if ($component->hasXmlBase() === true) {
            self::setXmlBase($element, $component->getXmlBase());
        }

        return $element;
    }