Day 25

 <data> The element associates <data>the content of the element with a programmatically readable value.

If the content is time or date related, then the element should be used <time>.

<dfn> Represents the definition of a term the first time it occurs.

<em> The element gives <em>emphasis to the text contained within it, and the element can be branched <em>(i.e. using more than one element <em>within each other) and each level of branching gives more emphasis to the text.