1) Yes. 2) Without a Sprint Goal, there would only be the Sprint Backlog to represent the Sprint plan. The Sprint Backlog might then consist of unrelated items. A Sprint Goal defines the purpose of the Sprint. In other words, without a Goal, the items on the Sprint Backlog may be too disjointed to result in a potentially releasable increment of value. 3) No, they are quite different. The Sprint Goal expresses the purpose of the Sprint. A Definition of Done defines the quality standard that each item on the Sprint Backlog must meet in order to be fit for inclusion in the increment. If a Sprint Backlog has been created well, no single item on it would be enough to satisfy the Sprint Goal (otherwise the Goal would be too trivial)...but each and every item would have to individually satisfy the Definition of Done.