Frodo crosses his arms and tries to think. Hm. His cousin does have a way of bending words in such a way to make the question seem even more profound.

"I suppose, if it were a memory then it would be difficult to find out," he looks to Bilbo to see if he can help think of the possibilities. Age, perhaps. "But if it were an object or an ability, then those are more easily felt. Could you think of any, Bilbo?"