The Earth formed 4.5 billion years ago[1], and life less than a billion years after that. Although life as we know it is dependent on four major macromolecules[2] – DNA, RNA, proteins and lipids – only one is thought to have been present at the
The Earth formed 4.5 billion years ago[1], and life less than a billion years after that. Although life as we know it is dependent on four major macromolecules[2] – DNA, RNA, proteins and lipids – only one is thought to have been present at the