What do the "Sync Internet" and "Sync Instant Upload" options do in Jelly Bean settings? What do the "Sync Internet" and "Sync Instant Upload" options do in Jelly Bean settings?
Instant Upload is a feature of Google+, which uploads the photos you take with your camera to a private photo folder on Google+ for easy sharing. This option allows you to enable/disable this feature, but it can also be controlled from other Google apps like Google+ and Google Settings. More info

Sync Internet means syncing your browser history, bookmarks, form input data and other settings on Chrome. This requires that you use the same Google account on all instances of Chrome that you want to sync. I'm not certain if this feature syncs the data also to the stock browser, but it's possible.