Thanks for the question.
While the Church has been approving of organ donation and such, it does not approve of whole body donation. In recent years, the Church has allowed cremation of remains, but it still wants the cremains to be placed in a sacred burial place, like a cemetery mausoleum created for such purposes.
The idea is that the Resurrection of the body is our hope and our handling of remains should reflect that article of faith. Granted there are times when bodies are lost to us in disaster and war and in other circumstances, but as a rule we try to reverence them in death because they are temples of the Holy Spirit, and we know, at some point, God will raise us to new life and reunite us with our bodies. Even though God is not limited to resurrecting our bodies by what remains are present in a particular tomb, nonetheless, we hold these remains as sacred and treat them accordingly.