Antibodies to common microorganisms have been developed by infancy. <span>An </span>antibody<span> (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to identify and neutralize pathogens such as bacteria and viruses.</span>
Probability: The chance of something happening and the likelihood of a particular event happening.
Most enzymes do in fact work on a single substrate in most cases, this is because of the enzyme - substrate specificity. Certain reactant molecules acting as substrates can only fit in the "lock" of particular enzymes and undergo a conformational change and result in Unique products to be released after the reaction has occurred.