Effects of Training on Athletes. Sports physiology is the study of the long-and short-term effects of training and conditions on athletes. This specialized field of study goes hand in hand with human anatomy. Anatomy is about structure, where physiology is about function.
Visa and Mastercard always have 16 digits whereas American Express has 15 digits. The short answer is that American Express cards have a different PAN format than Visa, MasterCard and Discover because they offer a different kind of financial service.
Where you find the security code depends on the card. If you have a Visa, MasterCard or Discover, turn the card over. In the signature box or just to the right of it, you will see a series of digits. However long the series, the final three digits are the security code. American Express cardholders can find their security code on the front of the card, either to the left or right of the embossed 15-digit card number.