CCDS-222 Database II 2nd _semster_2022_2023 2- (1pt) Why In a distributed database system, relational algebra is not enough to express the best execution strategies of queries? 3- (1pt) One way to minimize a cost function is to used the cost model approach. In that approach we can calculate the total cost and the response time cost. Define each of them? 4- (2pt) In the query processing methodology, explain the role of each layer: a. QUERY DECC MPOSTION. b. DATA LOCALIZATION. c. DISTRIBUTED OPTIMAZTION. d. DISTRIBUTED EXECUTION