What is "Tamei Nefesh"?
Rashi: A Mes itself.
Radak (12): The garment became an Av ha'Tum'ah via a Mes.
What was this question?
Rashi: A Mes is Avi Avos ha'Tum'ah (it makes what touches it an Av ha'Tum'ah. A [regular] Av makes a Rishon.) Therefore, what is a Chamishi due to Tum'as Sheretz (there were three intermediaries between the Sheretz and the last food), in such a case of Tum'as Mes, it is a Revi'i (for the first intermediary, a Kli, became an Av).
Radak (12): The garment (an Av ha'Tum'ah) touched meat, the meat touched the loaf, Nezid, wine or oil, and another food touched [what touched the meat]. The meat was a Rishon, it made a Sheni, so the last food is a Shelishi. They answered correctly (it is Tamei).
