The Nexus 5 was released on October 31, 2013.
The Nexus One was released back in January 2010, then released in other countries from March 2010 onwards. It was mostly available online on Google's web store (long before Google Play existed).
It has been released since 2012. The second generation was released in 2013.
The Galaxy Nexus was released on November 2011.
The two issues the Nexus One had on release were the touchscreen not functioning properly, and 3G connectivity. The OS updates reportedly fixed both issues.
Office have not been released for android. You can use apps like GoogleDrive.
The Motorola Nexus 6 ships with Android Lollipop but is upgrade able to Marshmallow. It has not been officially announced whether it will receive Android N.
The Nexus 5 was released on October 31, 2013.
Nexus One was created on 2010-01-05.
It is very easy for one to apply for a Nexus card. One can apply for a Nexus card by visiting the webpage called Get Nexus and filling out the quick and simple online form.
Since the question doesn't specify what Nexus the person is comparing it to the Nexus S, here's the order of Nexus phones (and by manufacturer) to date: -HTC Nexus One -Samsung Nexus S -Samsung Galaxy Nexus -LG Nexus 4 -LG Nexus 5
the Nexus One uses a mini SIM (regular SIM) card.