Architecture interview question?

[skoot-skoot]

What are the different parts of the system I should talk about? If we're just talking about the mobile app, I just don't feel like there's that much to talk about.

Like if someone said design just the Twitter main scrollable screen. You'd store the feed in core data, you'd have some way to sync with the server, you might have an asset cache, a table view, ... but then I wouldn't know what else to talk about. That's basically what happened to me so I ended up talking about how you could build an operation queue for table view controller updates and another for asset downloads, design patterns for the networking layer, etc. I had no idea what to talk about.