HTML - Necesito ayuda con HTML5

<form action="/action_page.php">

<select name="cars" multiple>

  <option value="volvo">Volvo</option>

  <option value="saab">Saab</option>

  <option value="opel">Opel</option>

  <option value="audi">Audi</option>

</select>

<input type="submit">

</form>