Context: A mordant or dye fixative is a substance used to set dyes on fabrics or tissue sections by forming a coordination complex with the dye which then attaches to the fabric or tissue. It may be used for dyeing fabrics, or for intensifying stains in cell or tissue preparations. The term mordant comes from the present participle of French "mordre", "to bite". In the past, it was thought that a mordant helped the dye bite onto the fiber so that it would hold fast during washing. A mordant is often a polyvalent metal ion. The resulting coordination complex of dye and ion is colloidal and can be either acidic or alkaline., Fiber or fibre (from the Latin fibra) is a natural or synthetic substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene., Green S is a green synthetic coal tar triarylmethane dye with the molecular formula C27H25N2O7S2Na . As a food dye , it has E number E142 . It can be used in mint sauce , desserts , gravy granules , sweets , ice creams , and tinned peas . Green S is prohibited as a food additive in Canada , United States , Japan , and Norway . It is approved for use as a food additive in the EU and Australia and New Zealand . Green S is a vital dye , meaning it can be used to stain living cells . It is used in ophthalmology , among fluorescein and rose bengal , to diagnose various disorders of the eye 's surface . Green S may cause allergic reactions and is one of the colorants that the Hyperactive Children 's Support Group recommends to be eliminated from the diet of children ., An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), in water would be represented as Na(aq) + Cl(aq). The word "aqueous" means pertaining to, related to, similar to, or dissolved in water. As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry., Color (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color "categories", with names such as red, yellow, purple, or bronze. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them. This reflection is governed by the object's physical properties such as light absorption, emission spectra, etc. Human trichromacy is the basis for all modern color spaces that assign colors numerical coordinates and associate corresponding distances between colors., A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is generally applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber., Subject: green s, Relation: has_part, Options: (A) a (B) affinity (C) carbon (D) cell (E) chemistry (F) english (G) fiber (H) french (I) human (J) light (K) metal (L) s (M) salt (N) solvent
Output: carbon