Living organisms are composed of millions of organic compounds, each having a unique structure. what element is responsible for this huge diversity of molecules? describe the diversity of structures that can be formed and the properties of this element that allow this diversity of form to occur

The answer is carbon.

The reason this element gives so much diversity is due to its valency of +4. This means it can bond with many elements in different ways to form different compounds. Carbon can also bond with other carbon atoms in many different ways (from linear chains, branched chains to rings). It is due to this versatility that carbon is the central elements of organic life. The different organic molecules that carbon is the central atom is DNA, carbohydrates, proteins, lipids, and etcetera.  

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products

this is more of a statement than a question. is there answers to go along with this, or is it opinion based?