Handling of empty content and white space-only content?

I'm curious if XML says anything about how XML processors are to
handle 1) empty content in an element, and 2) when the content
contains only "white space" characters. If XML is silent, am I right
to assume it is up to the application to decide how these situationas
are processed and used?

Examples:

   <foo></foo>

   <foo>  </foo>

Oh, and I've also been curious if there's any specified rules when
parsed contain starts and/or ends with white space within an element.
For example:

   <foo> some content </foo>


Thanks!

Mark
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  Mark O. Zorro
  

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