The concentration of 12C is further increased in biological materials because biochemical reactions discriminate against 13C.. 
Meli yi ko da wa fun ra ara rẹ nikan ni idaye, ṣugbọn bẹ o wa ni àdapọ; o kọkọ jẹ pipin latọwọ huẹ̀fọ́ Davy ni 1807 pelu elekAB hasisi Haid-di Sodi’’ 