<Dl> <Dd> This means that the joint tenants must have the same type of interest, and the interest must run for the same duration . For example, if X and Y create a joint tenancy, both X and Y's interests must be in fee simple absolute . If, for example, X has a fee simple absolute and Y has a life estate, there is no unity of interest . </Dd> </Dl> <Dd> This means that the joint tenants must have the same type of interest, and the interest must run for the same duration . For example, if X and Y create a joint tenancy, both X and Y's interests must be in fee simple absolute . If, for example, X has a fee simple absolute and Y has a life estate, there is no unity of interest . </Dd> <Dl> <Dt> Unity of possession </Dt> <Dd> Both tenants must have the right to possess the whole property . </Dd> </Dl> <Dt> Unity of possession </Dt>

Which of the four unities is the only one that a joint tenancy and a tenancy in common both share