Which type of code represents the view in the MVC architecture on the Force.com platform?

Given:
Map<ID, Account> accountMap = new Map>ID, Account> ([SELECT Id, Name FROM Account]); What are three valid Apex loop structures for iterating through items in the collection? (Choose three.)

Application Events follow the traditional publish-subscribe model. Which method is used to fire an event?

Where can the custom roll-up summary fields be created using Standard Object relationships (Choose 3)

Universal Container use a simple order Management app. On the Order Lines, the order line total is calculated by multiplying the item price with the quantity ordered. There is a Master-Detail relationship between the Order and the Order Lines object.
What is the practice to get the sum of all order line totals on the order header?