regarding items one cannot use for insulating food where a similar list appears of items that create heat, they notice that stones appear here and not there and sand appears there and not here. Why? Why is it necessary to mention both distancing seeds and a plow? Why do seeds need to be distanced? The Mishna rules that urine must be distanced from another's wall. However, Raba bar bar Hana rules that one can urinate next to another's wall. How can his statement be explained in light of the Mishna? Even though the Gemara suggests an explanation, they reject Raba bar bar Hana's statement in light of a braita. Shmuel ruled that a wafer placed in a window does not block impurities from a dead body from passing through. A contradiction is brought from a Mishna in Ohalot 6:2, but is resolved.