In which TV series is Mr. Feeny a main character?

Who played Al Borland in 'Home Improvement'? Who played Cory Matthews in 'Boy Meets World'? Who played Topanga Lawrence in 'Boy Meets World'? Who played Mr. Feeny in 'Boy Meets World'? Who played Fox Mulder in 'The X-Files'? In which TV series is Fox Mulder a main character? Who played Dana Scully in 'The X-Files'? In which TV series is Dana Scully a main character?