Subject: Are dead things considered biotic or abiotic?

My 8th grade class is studying ecology.  We are quite familiar with the idea of
biotic and abiotic factors within an ecosystem.  The question that keeps coming
up is what about things that have died.  Is a leaf that has fallen from a tree
abiotic or biotic?  What about a twig?  What about paper?  What about a dead
animal?   They are technically not living but do come from living things.  Where
should we group them?

Re: Are dead things considered biotic or abiotic?