For credit card processing, stock exchanges, and airline reservations, data availability must be continuous. there are many other examples of mission-critical applications. research the internet to find four additional mission-critical applications and explain why data availability must be continuous for these applications. if you use information from the web, use reputable sites. do not plagiarize or copy from the web. be sure to cite your references.

Write a method named addall that could be placed inside the hashintset class. this method accepts another hashintset as a parameter and adds all elements from that set into the current set, if they are not already present. for example, if a set s1 contains [1, 2, 3] and another set s2 contains [1, 7, 3, 9], the call of s1.addall(s2); would change s1 to store [1, 2, 3, 7, 9] in some order. you are allowed to call methods on your set and/or the other set. do not modify the set passed in. this method should run in o(n) time where n is the number of elements in the parameter set passed in.

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

The option enables you to modify a slide element in most presentation applications.