While surfing online, patricia checks her email and reads the latest messages. she then browsers a website and logs in a comment. arrange the protocols in the order they are used.
tcp for email
ip for website
http
ldap
ip for email
pop3
tcp for website

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Explain how email technologies enable the exchange of messages between users. find out the typical parts of an email address and explain each part.

If you want to delete an entire word at a time, which key should you press along with the backspace or delete key?