Bava Batra 92: Let the Buyer Beware (Or Not?)

Beginning chapter 6 - with a new mishnah. One who sells produce that is sometimes used for eating and sometimes for planting -- what happens if the buyer plants the item and it doesn't grow? What if one sells an ox and it turns out to be a gorer? When is the seller responsible for the dud of the sale? Plus, when does the issue of "rov" - the majority, especially in terms of expectations - kick in, especially since it's rarely applied in the context of monetary dealings.