In the formal language of economics, X and Y are substitutes if the demand for X increases when the price of Y increases, or a positive cross elasticity of demand.
Potting mix is the material that goes into a garden pot before you put seeds and plants into it. 1  It keeps the plant in place. 2  It holds water for the plantâs roots to soak up.  It contains nutrients that feed the plant.
Background. Slime is a unique play material composed of a cross-linked polymer. It is classified as a liquid and is typically made by combining polyvinyl alcohol solutions with borate ions in a large mixing container. It often has an unpleasant odor, a green color, and is cold and slimy to the touch.hile the intermixing of the polymer strands will give some built-in viscosity, a cross-linking agent is also present in slime to give it the non-Newtonian fluid behavior. Cross-linking agents are ions that help temporarily connect polymer strands with relatively weak ionic bonds.