empty spaces caused by HTML tag <ul>

Question

Here's my html code:

      <nav class="first_nav">
        <ul>
          <li><a href="#">Vehicles</a></li>
          <li><a href="#">Energy</a></li>
          <li><a href="#">Charging</a></li>
          <li><a href="#">Discover</a></li>
          <li><a href="#">Shop</a></li>
        </ul>
      </nav> 

Between "li" me I see characters that are selectable, but that only disappear when I delete "ul". What could it be? And how do I fix it?

I tried removing and adding styles in CSS and still nothing changed. The only way I could make those "empty" characters disappear was by erasing . I have list-style:none and text-decoration:none as well.