I don't know where you are getting your information from, but the network that first broke the story reported that Clinton did not set up a State.gov email address during her tenure at the State department. If you're reading anything else, you should probably vet your information.
http://www.nytimes.com/2015/03/03/u...department-raises-flags.html?smid=tw-bna&_r=3
If that is the case, then she had multiple private emails. Either way, much of her correspondences was done through Clintonemail.com.
You're thinking too much into this. The question is pretty clear. Her email address isn't encrypted. If Clinton used her private email address to exchange emails to members of the Obama administration, wouldn't anyone have found this out by now?
That is not a possibility. There is only one email address that we know about. If there are others, it's not from the state.gov server.
Obama has claimed that he has heard many things from the news. This isn't new. If anything, it puts his alertness and competency into question, but it's not like it matters anymore since he will be gone in a year or so.
This issue lies with Hillary more than Obama. Considering Hillary's private servers are such a security fail, this shows why her candidacy is highly questionable...