Because some features may not be available on some browsers. By viewing it on different browsers, we can see if there's any incompatibilities and fix them. 
 
        
             
        
        
        
Drag... you drag the mouse across the screen.
        
             
        
        
        
The answer would be A: wireframe, im pretty sure...
Hope this helped!! :)
        
                    
             
        
        
        
Answer:
a. (p*Main).age = 20;
Explanation:
Pointers use ->
where as normal variable use . to access its members
pMain is the pointer.
*pMain is the value inside pMain.
pMain->age = 20;
This statement equals to 
(*pMain).age = 20;
Answer is option a.