is wikipedia a reliable source ?

If you look at the sources used at the bottom of the article, you'll have many reliable sources to use, and big Wiki articles are pretty reliable. 

It depends greatly on the subject.

You can always go to the links that are provided (or simply spend some time googling other sources for the same information) to verify it.

No it is not. Anyone can edit pages, and subpar sources are often used to back up claims. This is primarily why teachers rightfully inform their students not to use Wikipedia as a source. 

Not necessarily, but the resource to support what is written should be at the bottom of the article.

No, the Berlin Wall went up 12 August 1961 I know I was On duty on a Nuclear weapons squadron in Germany at the Time Every time i get it changed some Moron changes it back to the 13 August

so i never use Wiki as a source

Yes ,it is! this one trustable source!

yes , but the sources come from the public ..its like freeware , some freeware is excellent , so why pay ..

No.  It is not a peer reviewed source. However, most of the basic information is accurate.  

No. I wouldn't trust anything on that site anymore. The gay community put up some nonsense about genders to try and legitimize their mental disorders and I believe others also put up wrong information for legitimacy. There are to many nefarious people to believe a site where anyone can post any nonsense they want.

No of course not. It has its own agenda of what is fact or fiction