food contains nutrients for living things & dead organisms are the source of nutrients for decomposers ->  dead organisms are the source of food for decomposers  dead organisms are the source of food for decomposers & if an object is a source of something for something else then that something else can obtain that something from that object ->  decomposers obtain food from dead organisms  decomposers obtain food from dead organisms & absorbing something is a kind of method for obtaining something -> decomposers obtain food by abosorbing food from dead organisms