Usage of commenting out

Tell us what’s happening:
could u please tell me what is the usage of commenting out with . after adding that, didn’t see any difference.

Your code so far

<!-- <link href="" rel="stylesheet" type="text/css">-->
.red-text {
  color: red;

h2 {
  font-family: Lobster,Monospace;}

p {
  font-size: 16px;
  font-family: monospace;

<h2 class="red-text">CatPhotoApp</h2>
<p class="red-text">Click here to view more <a href="#">cat photos</a>.</p>

<a href="#"><img src="" alt="A cute orange cat lying on its back."></a>

  <p>Things cats love:</p>
    <li>cat nip</li>
    <li>laser pointers</li>
  <p>Top 3 things cats hate:</p>
    <li>flea treatment</li>
    <li>other cats</li>

<form action="">
  <label><input type="radio" name="indoor-outdoor" checked> Indoor</label>
  <label><input type="radio" name="indoor-outdoor"> Outdoor</label><br>
  <label><input type="checkbox" name="personality" checked> Loving</label>
  <label><input type="checkbox" name="personality"> Lazy</label>
  <label><input type="checkbox" name="personality"> Energetic</label><br>
  <input type="text" placeholder="cat photo URL" required>
  <button type="submit">Submit</button>

Your browser information:

User Agent is: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_1) AppleWebKit/604.3.5 (KHTML, like Gecko) Version/11.0.1 Safari/604.3.5.

Challenge: Specify How Fonts Should Degrade

Link to the challenge:

Hi @SARA1985

The point of this challenge is to demonstrate the importance of specifying more than one font-family. When one is not available, your page can use one of the other fonts specified. Before commenting out the link, your h2 header uses the Lobster font and it looks like image
When you comment the link, your h2 tag uses monospace now that Lobster font isn’t available.image


okk. got it. thankss!