Question 3 : what tool can diagnose and fix many common linux filesystem problems?

The tool that can diagnose and fix many common linux file system problems is fsck.  fsck, is Linux's file system check utility. It's similar in purpose to the DOS and Windows CHKDSK and ScanDisk utilities. 

Answer the important painting of the baptism of the christ, leonardo painted the kneeling angel and some of the background for this;

Placeholders  are the containers in  layouts  that hold such content as  text  (including body  text, bulleted lists, and titles),  tables,  charts, smartart graphics, movies, sounds, pictures, and clip art.  slide layouts  also contain the theme (colors, fonts, effects, and the background) of a  slide.