What line of HTML would you use to reference an external style sheet?

If a layout is created in a PSD with blue buttons in the nav, then it would be best for the speed of the page to:

When style in different locations conflict, which will take precedence?

In webkit, in order to set the transition duration you must first:

To change the state of a selector you must change its:

How would you add three columns to a page using CSS3

All properties must have a:

What is the earliest version of Internet Explorer that supports border-radius?

In HTML5, how can you visually center this <div class="center">hi</div>?

Pick the INCORRECT selector

Which of the following transitions follows the correct format?