“Require only 25 elements for a healthy life to create all the blood bone muscle and other tissue from which our bodies are formed. This is so-called essential elements are shown in table 2. 1. indeed, just for elements hydrogen carbon oxygen and nitrogen make up almost 97% of the total body mass, and constitute a staggering 99% of the total atoms from which the body is formed. Every element has been given a name (four example, hydrogen nitrogen and oxygen) and, for convenience, has also been assigned a one or two letter shorthand single. Just as we have a shorthand symbol. Just as we have a shorthand notation for the nuclear tide basis that make up DNA and RNA (G, C, A, T, and U and), Social and symbols for the chemical elements give us a way of communicating exactly what is taking the substance of material contains at a glance. So. Oxygen is represented by the letter O, Hydrogen by the letter H, and nitrogen but the letter N. we will employ those chemical symbols throughout this book”.
by Jonathan Crowe, Tony Bradshaw, Paul Monk, in chemistry for the biosciences.