It was time to register the new semester. Sarah was excited. a quick breakfast, she logged into school's website. As she clicked through course catalog, Sarah felt a little . She had heard that some classes up quickly. With a deep breath, selected the history class and added to her cart. Then, she moved to her other choices, like art, , and so on. Her classes were available. They fit perfectly into her . Sarah reviewed her choices, making sure had selected all the classes she to take. Then she clicked the "" button. A message appeared on the confirming her enrollment.