Placing one open window on top of another open window with just the title bar and a portion of the border visible, is known as ________

Which of the following is NOT true about YouTube?

A) YouTube serves as a repository for "historical" items, such as old television commercials, music videos, and clips from classic television shows. B) Videos you upload cannot contain any copyrighted content, including any commercial music that may be playing in the background. C) Videos may not contain offensive or adult content. D) YouTube accepts videos up to 30 minutes in length.

Most operating systems offer a(n) ____________________ designed for professional troubleshooting.

Fill in the blank(s) with the appropriate word(s).