1. The CSS "box model" is a box that wraps around every HTML element. (e.g margins, borders, etc.)

2. The difference between margin and padding is that. Margin deals with the outer space where as the padding deals with the inner space

3. The height and width of an HTML element is determined by px, cm, percents, and by inheritation

4. The CSS property padding: 25px 50px defines the top and bottom of the element to be 25px and the right and left of the element to be 50px