Carbon Carbon is the second-lightest element essential to life. Most of the carbon we have comes from carbon dioxide which is in the air we breath. Carbon makes up a large amount of where plants gain their mass from. As with the other elements, carbon is distributed across the universe by stars going supernova. Oxygen Oxygen is essential to all eukaryotic cells. The oxygen we breath comes from our atmosphere, but makes up less than 25% of it. As with the other elements, it is ejected across the universe when stars go supernova.  |
Hydrogen Hydrogen is the most abundant element in the universe and accounts for over 70% of all atoms. All hydrogen was formed at the start of the universe and is what is being fused in the earliest stages of a star's life. Hydrogen is constantly ejected across the universe when stars go supernova. Nitrogen Every living thing uses nitrogen. Nitrogen accounts for about 78% of our atmosphere and decays at a constant rate. Due to this constate rate scientists estimate the amount of nitrogen in the atmosphere when sometime dies and then come up with an estimated time when it died. This is called carbon dating and is how scientists date things like fossils. |
