Several ways you can determine the validity is
1.) The author and his credentials.
2.) Sources that back up the article/publication.
3.) Whether the article features bias or none, when appropriate.
My friend, Alex, plays tennis.
My = possessive pronoun
friend = subject
Alex = an appositive (which is a noun that renames another noun right beside it) -- though not an adjective, it functions like one to explain which friend
plays = verb
tennis = direct object
hope this helps :)
C. Giggles, Cause when you giggle, it's usually cause something is funny.