When a url ends in a folder name instead of a file name, the server automatically looks for a file called: ?

What type of weird relationship this is analogy show? dissolve: solidify: : noise: silence

Under which key category do the page up and page down keys fall? page up and page down keys fall under the keys category.

How would you categorize the software that runs on mobile devices? break down these apps into at least three basic categories and give an example of each.