What is mulch and give two materials that can be used as mulch

mulch isnt really something itsself, if that makes sense.

Explanation:

A variety of materials are used as mulch: Organic residues: grass clippings, leaves, hay, straw, kitchen scraps comfrey, shredded bark, whole bark nuggets, sawdust, shells, woodchips, shredded newspaper, cardboard, wool, animal manure, etc.