The difference between a URI and a URL is that a URL is like a complete mailing address with street address, City, State, on a shipping label. URI is just the address.
If someone were to ask you where you lived and you just said 8 Lincoln Heights.. they would not be able to locate you because there might me 8 Lincoln heights street names in different cities around the country. This would be an example of a URI. By including the City, and state, Alson, Nevada along with 8 lincoln heights..everyone could now locate you.
So a hostname + folder location = URL.
HTTP ELEMENTS REVIEW
When the browser receives a http request it returns data to the browser in a graphical way. To do this text is marked up or formatted with Tags. Text enclosed in a <p> tag will be formatted visually in the browser like a paragraph. An text representation of an image displayed visually to the browser will be formatted like <img src=”http:image.com/myimage.jpg”/>
