The wars of Alexander the Great were fought by King Alexander III of Macedon (The Great), first against the Achaemenid Persian Empire under Darius III, and then against local chieftains and warlords as far east as Punjab, India.
What are the four most abundant elements found in living systems? There are 4 very abundant elements found in living systems. These 4 abundant elements are oxygen, carbon, hydrogen, and nitrogen.
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.