Answer:
When executing Agile Projects, an iteration, is a timebox (a fixed period of time when activity takes place) during which development is carried out. Depending on the project, an iteration may last between 7 to 28 days.
As far as the Agile Manifesto is concerned, the short development cycles of or iteration means that priorities can be moved between iterations. It also means that features of an Agile project can be modified on or before the next iteration.
In traditional project managagement this sort of revisions is called scope creep. That is when a project deviates from or expands upon it's original deliverables before the project is over. This is usually a problem. The Agile methodology however allows for revisions to happen within timeboxes. Thus ensuring that regardless of addition of new features, the time set for the development is not exceeded.
It is the view of Agile Project Developers that the iterations allow for provision of additional value and improvement.
Cheers!
