Classical conditioning may be defined as a type of learning in which the potent stimulus is combined with neutral stimulus and produces a great response.
The Pavlov explains the classical conditioning learning. The sound of the bell here acts as the unconditioned stimulus because this stimulus helps the dog to salivate when combined with the strong stimulus. The neutral stimulus is here to evoke the response.
The skill used at the beginning of a race is reaction time because you want to start running the moment the race starts so you have to be ready and have good reaction time.