Here is an HTML example with the CSS class defined inline:
<!doctype html>
<html>
  <head>
    <style>
   .YellowBackground {
  background-color : yellow;
   }
 </style>
    
    </head>
  
    <body class="YellowBackground">
        <h1>A yellow background</h1>
    </body>
</html>
 
        
             
        
        
        
VoIP stands for Voice over Internet Protocol. VoIP <span>is a digital telephone </span>service in which calls are sent and received over the Internet. High speed Internet connection a VoIP phone service <span>provider are </span><span>needed in order to have this type of service. </span> 
It is true, that VoIP service is interrupted during a power failure. You should <span>have </span>backup power supplies to support your VoIP network when the power is out in order to have uninterrupted service. 
        
             
        
        
        
Answer: Hyperpersonal communication
 
Explanation:
In this type of communication we have inter personnel communication mediated through computers such that there is more scope for textual messages than face to face communication.