Quick question -Sql regarding functional dependencies, can you help?

Not sure - I can think of a number of possible interpretations of what the arrow is supposed to mean. (I would suggest you look earlier in the text...chances are it's defined there.) The two that immediately came to mind are 'is an example of' and 'is used to create', but only the latter seems likely in this context. In that context, apples are required to create some aspect of bananas and so is yogurt. However, apples may have no impact on creating yogurt at all. (This is more easily grasped if you replace apples, yogurt and bananas with axles, doors and cars, respectively.)