Rabbi, I understand that we are not allowed to donate our organs after we are Niftar. Does this apply to all organs? And please let me know the reason for not allowing this. Thank you very much.

The terms of donating organs depend not only on Halacha, but also on the laws of that country. It is most important that the whole procedure is done with appropriate Halachic supervision since it is very easy to disregard respecting the dead and to not handle the organs accordingly during this process (something which happens many times in such cases). Rabbi Ro'i Margalit