1)
Reliability of Wikipedia depends on source and context.
The word "source" when citing sources on Wikipedia has three related meanings:
the piece of work itself (the article, book);
the creator of the work (the writer, journalist),
and the publisher of the work (for example, Random House or Cambridge University Press).
There are some types of sources. Scholarship, News organizations and biased or opinionated sources.
But self-published sources are not good reliable sources.
In general, the more people engage in making articles delicate the more articles are reliable.
So It is important for people to participate to edit a article.
Criticism of Wikipedia is related to accuracy of information, quality of the presentation,
systemic bias in coverage, sexual content, exposure to vandals and privacy concerns.
2)
There are too much information online which are not certainly right.
So It is very important to more people to edit one article to make it
reliable. Because All wikipedians are not experts, so we need to help each other.
3) The part,
"Primary, secondary, and tertiary sources" is hard to understand.
I would like to discuss it and want your explanation.