From what grains does one fulfill one’s obligation to eat matza. Only from one of the 5 grains. What is the source for this? The rabbis and Rabbi Yochanan ben Nuri debate the status of rice and millet both for fulfilling the mitzvah of matza using them and for receiving the punishment of karet if one eats them leavened on Pesach. Do they really leaven or not? Is one allowed to eat kitniot on Pesach? What is the status of a dough made with fruit juice, wine or honey that rose? Does one get karet for that?  Do we say that since one can’t fulfill one’s obligation for matza with a dough like that, as it is not poor man’s bread, then one is not obligated karet if it leavens? The Mishna lists situations in which one can or cannot fulfill one’s obligation of matza for an outside reason – either it is permitted or forbidden because of a different halachic issue. The gemara goes through each case and explains either why or asks why is this mentioned – isn’t it obvious?