William has an internet connection that does not allow him to make calls when connected to the internet. what internet service can he use over his existing telephone line that will enable him to make calls and browse the internet at the same time?

a. dial-up
b. isdn
c. cable internet access
d. satellite internet access

3. bob is arguing that if you use output feedback (ofb) mode twice in a row to encrypt a long message, m, using the same key each time, it will be more secure. explain why bob is wrong, no matter what encryption algorithm he is using for block encryption (15 points).

Dean wants a quick way to look up staff members by their staff id. in cell q3, nest the existing vlookup function in an iferror function. if the vlookup function returns an error result, the text “invalid staff id” should be displayed by the formula. (hint: you can test that this formula is working by changing the value in cell q2 to 0, but remember to set the value of cell q2 back to 1036 when the testing is complete.)

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