What is the purpose of creating a primary key in a database

Suppose we have a byte addressable computer that has a 32-byte cache with 8 bytes per block. the memory address is 8 bits long. the system accesses memory addresses (in hex) in this exact order: 6e, b9, 17, e0, 4e, 4f, 50, 91, a8, ab, ad, 93, and 94. (a) assuming the cache is direct mapped, what memory addresses will be in cache block 2 after the last address has been accessed? (b) assuming the cache is direct mapped, what is the hit ratio for the entire memory reference sequence given, assuming the cache is initially empty? (c) assuming the cache is 2-way set associative with a lru replacement policy, what is the hit ratio?

Arecipients list has been loaded into a document. which commands should be clicked in order to filter the list so that letters will not be printed for recipients who live in a certain state? mailings tab, start mail merge, select recipients, type new list, then insert only contacts from the desired states mailings tab, rules, select recipients, use existing list, then choose a recipients list that includes only contacts in certain states mailings tab, select recipients, use existing list, rules, fill in, then type in certain states mailings tab, rules, skip record select “state” under field name, then type in the state name under “equal to”

Which of the following is not a way in which trees benefit the environment? a. they remove a significant amount of carbon dioxide from the atmosphere. b. they remove a significant amount of oxygen from the atmosphere. c. their roots hold soil in place, reducing rates of erosion. d. they remove ozone and particulates from the atmosphere. select the best answer from the choices provided a b c d