In regards to ER Models, which of the following are correct? (select all that apply) 1. Strong entities have a distinct and independent existence 2. An entity occurrence is a uniquely identifiable object of an entity type oe 4. Composite attributes are usually represented as relations in the relational model 5. A relational schema derived from an ER model should be validated using the rules of normalization so that it satisfies various constraints to avoid unnecessary redundancy