The origin of replication (also called the replication origin) is a particular sequence in a genome at which replication is initiated.
It is the interaction of two or more substances, resulting in chemical changes in them. Chemical reactions take place when some kind of energy is supplied to them. The supplied energy may be in the form of heat, light or mechanical shaking for proper contact between the reactant molecules or electricity.
Best Answer: An endothermic reaction needs energy to work, to create the molecules bonding, for example Melting of ice. An exothermic reactions generates energy, molecules break their bonding and thus leberating energy, for example fuel combustion.