Riemann's green is a green pigment ZnO.CoO, which is obtained by heating a mixture of zinc oxide and cobalt nitrate or by the reaction of cobalt nitrate with either or zinc sulphate.
Water is a vital substance for life on Earth, and it plays numerous important biological roles in living organisms. Some of the key biological roles of water are:
Universal solvent: Water is an excellent solvent for many substances, both organic and inorganic. This means that it can dissolve and transport a wide range of nutrients and minerals necessary for the growth and survival of living organisms.
Medium for metabolic reactions: Many metabolic reactions in living organisms require water...
A negative of a vector represents the direction opposite to the reference direction. It means that the magnitude of two vectors are same but they are opposite in direction.
For example, if A and B are two vectors that have equal magnitude but opposite in direction, then vector A is negative of vector B.
