Copy-Paste graphics from pdf into Keynote

Hi everyone,

When preparing presentations (in Keynote or PPT) I often need to copy selections (graphics, not text) from PDFs and paste them into Keynote/PPT. So far I'm still looking for a PDF reader for iPad that lets me do that. Some allow you to copy text, but I'm still looking for one doing that for graphics. My questions are:

(1) Does anyone know whether you can copy-paste in principle from another application into Keynote on iPad? I think it should be possible, but you never know...

(2) What PDF reader would be able to do that (if any)?

Thanks in advance!