Examples of index fossils. Index fossils (also known as guide fossils, indicator fossils or zone fossils) are fossils used to define and identify geologic periods (or faunal stages).
Methyl cellulose. Methyl cellulose (or methylcellulose) is a chemical compound derived from cellulose. It is a hydrophilic white powder in pure form and dissolves in cold (but not in hot) water, forming a clear viscous solution or gel.
RELATED ARTICLES. Cellulose is a polysaccharide (a form of carbohydrate) that has a structural role in animals and plants. In plants, cellulose is the compound that gives rigidity to the cells. The bonds between each cellulose molecule are very strong, which makes cellulose very hard to break down. Because there are so many plants in the world (think of all the flowers, trees, weeds, grasses, vines, and bushes), cellulose, which is found in every cell of every plant, is the most abundant organic compound on earth.