Truly modern molecular biology emerged with the uncovering of the structure of DNA in the 1960s and concurrent advances in biochemistry and genetics. Molecular biology is one of three primary molecular-scale biological sciences, the others being biochemistry and genetics.
1 Students should know the parts and functions of the circulatory and respiratory systems and how they work together for respiration. 2  Students should also understand what homeostasis is and that all living things must be able to maintain homeostasis.
Best Answer: Oxygen is a pure element while Carbon Dioxide is a compound. We breathe Oxygen in and Carbon Dioxide out. An Oxygen molecule has 2 atoms while a Carbon Dioxide has 3. They have different names. Carbon Dioxide is poisonous (In large quantities), Oxygen isn't. Oxygen feeds a fire, Carbon Dioxide puts it out.