All Acronyms. CTA - Control Terminal Agency [Internet]; April 13, 2017 [cited 2017 APR 13]. Available from: https://www.allacronyms.com/CTA/Control_Terminal_Agency.
There are almost 120 known elements. For example, you are made up of billions of billions of atoms but you probably won't find more than 40 elements (types of atoms) in your body. Chemists have learned that over 95% of your body is made up of hydrogen (H), carbon (C), nitrogen, oxygen, phosphorus (P), and calcium (Ca).
Scientists believe that about 25 of the known elements are essential to life. Just four of these â carbon (C), oxygen (O), hydrogen (H) and nitrogen (N) â make up about 96% of the human body. These four elements are found in the basic structure of all biochemical molecules.