What does a Gram Negative stain show? - Stains the background of bacteria - The dye does not stick to the specimen, instead settles around its boundaries, creating a silhouette
A chemical element is a pure substance which is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number and represented by the symbol Z. The mass number is the sum of the number of protons and neutrons in a nucleus.
Substance. Definition. noun, plural:substances. (1) The physical matter, material or that of which an organ or body consists. (2) (chemistry) A material, matter or that which has definite chemical composition and distinct properties.(3) The most vital or essential part of something. (4) Drugs, as in substance abuse.oun, plural:substances. (1) The physical matter, material or that of which an organ or body consists. (2) (chemistry) A material, matter or that which has definite chemical composition and distinct properties. (3) The most vital or essential part of something. (4) Drugs, as in substance abuse.