Take the time to watch this YouTube video covering enterprise architecture from the Department of Defense Acquisition program perspective.The video...

Take the time to watch this YouTube video covering enterprise architecture from the Department of Defense Acquisition program perspective. The video is approximately 80 minutes in length. It takes about the first 10 minutes before switching to the architecture topic so please be patient. 

The video, in the simplest form, describes architecture as "the structure of components and their relationships, in a logical, purposeful manner".

Source:  Video on Enterprise Architecture

Please answer the following questions:

1. From the video, define "architecture viewpoints". Why are they so important?
2. List some (2-3) of the most important things to consider when creating or maintaining an enterprise architecture.
3. Why is it important to document your architectural decisions?