What os block level or inline content???

Answer 1

inline when you don't have closing tag, for example <img /> tag and block level is when you have closing tag like <p></p>

Answer 2

Example:

self-closing but not inline
<embed>
<hr/>

inline but not self-closing
span, i, b, a, lebel, sub, sup etc.

Answer 3

@Вукан
All self-closing tags aren't inline and vice-versa.