Third, magnetism in rocks can be used to estimate the age of a fossil site. This method uses the orientation of the Earth's magnetic field, which has changed through time, to determine ages for fossils and rocks.
Some animals, particularly ruminants and termites, can digest cellulose with the help of symbiotic micro-organisms that live in their guts, such as Trichonympha. In humans, cellulose acts as a hydrophilic bulking agent for feces and is often referred to as a  dietary fiber .
1 The most economical choice for cellulose comes from wood by-products, however cellulose can also come from vegetables, but will be listed on the label as such. 2  The cellulose wood pulp industry is at itâs all time high (up 8% from 2009-2011). 3  Humans cannot digest cellulose. 4  It has no caloric value.