E-Commerce websites are online portals that facilitate online transactions of goods and services through means of the transfer of information and funds over the Internet. In the early days, e-Commerce was done partially through emails and phone calls. Now, with a single website, anything and everything that a transaction needs, can be executed online.
Responsive Design is a design philosophy where in the design of the system (the representation and the layout) responds/adapts depending upon the layout of the device. The primary reason to keep your design responsive is to increase the reach of your application to a larger user base using an array of devices.
Web development broadly refers to the tasks associated with developing websites for hosting via internet. The web development process includes web design, web content development, client-side/server-side scripting and network security configuration, among other tasks.
Web development is also known as website development.