Use ________ spacing to improve readability of a document by changing the default spacing between characters

Some social media widgets use the HTML __________ element, which enables developers to embed content from another website while preserving formatting and presentation that may look quite different from the surrounding web page.

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

Color ____ are identifiers that are only visible in Photoshop and that enable you to locate specific areas of color while you’re adjusting your image.

a. values b. indices c. thresholds d. markers