It's an optional feature. It also has Dual-band Wi-Fi.
Yes, the Nexus 7 comes in LTE versions.
Yes, the Nexus 7 4G does take a SIM card. If you are purchasing directly from Google, you can choose either an AT&T or T-Mobile SIM, which is provided.
There are various types of Nexus devices, but the Nexus 7 is part of that same family.
The Nexus 7 is an Android Tablet made by Google. It has a screen size of 7 inches.
If you buy an LTE version yes. If you buy wifi only then no.
Yes, it has Google Play.
No, you will have to download a movie to a Nexus 7 tablet on your own.
It is a tablet.
Not really, unless you count the Google and Nexus branding as "ads".
Only if you buy an LTE version. Wifi only versions do not require a data plan.
Yes you can.
The 7 in Google Nexus 7 has not been openly mentioned to stand for anything. However, the recent Nexus tablet iterations (and to some degree, the phone as well) appear to refer to screen size. Both generations of the Nexus 7 have 7 inch and 7.02 inch screens respectively. The Nexus 10 has a 10.1 inch screen. The Nexus 4 has a 4.7 inch screen. The rumored Nexus 5 is supposed to have a 5 inch (or larger) screen.