A. Responsive Web Design- an approach to web design aimed at crafting sites to provide an optimal viewing experience—easy reading and navigation with a minimum of resizing, panning, and scrolling—across a wide range of devices (from desktop computer monitors to mobile phones) (wikipedia)
B. Responsive Web design is important because it makes a more user friendly interface to your website. If the site looks bad on mobile the user won't want to bother with it but the resposive design invites the user to use the site. a place in a computer program where the sequence of instructions is interrupted, especially by another program or by the operator.
C. Media Queries- a CSS3 module allowing content rendering to adapt to conditions such as screen resolution (e.g. smartphone screen vs. computer screen). It became a W3C recommended standard in June 2012. and is a cornerstone technology of Responsive web design.(wikipedia)
D. Breakpoints- a place in a computer program where the sequence of instructions is interrupted, especially by another program or by the operator.
One of the best responsive websites is the Boston Globe: http://www.bostonglobe.com

The smallest version has only one story to the top, the menu is a button on the top, there are no ads, and the font gets a little bigger

For the 2nd smallest version of the site it loses the menu at the top, it moves one of the top stories down, and the font gets bigger

The biggest version has a menu bar at the top, the images are bigger, its has three stories at the top, and the font gets a little smaller.
