scraping an object may cause small particles to break off of that object & a rock is a kind of object ->  scraping a rock may cause small particles to break off the whole rock  scraping a rock may cause small particles to break off the whole rock & glacier may scrape rocks when it moves ->  glacier can scrape a rock and cause small particles to break off the whole rock  very small rocks / minerals are kinds of of small particles & soil is made of very small rocks / minerals ->  soil is made of small particles of rock / minerals  glacier can scrape a rock and cause small particles to break off the whole rock & soil is made of small particles of rock / minerals -> the small particles of a rock scraped by the glacier can make up soil