Quick response case question

suppose Amazon. was recently sued because of an accident caused by one of their contract delivery drivers. Amazon had often used the same drivers from Vancouver because they knew the Lower Mainland area extremely well. While the drivers were able to pick up shifts as they wanted, Amazon supplied the delivery vans they used. Amazon also handled some of the larger expenses, such as vehicle maintenance and insurance and most of the drivers worked exclusively for Amazon. According to the lawsuit, the driver had been completing a delivery when his vehicle approached a crosswalk. He did not brake hard enough and struck Ms. Kia who was crossing the street. When the emergency technicians began treatment on Ms. Kia, they discovered that she had a rare muscle disease which meant that her body was less able to absorb the shock of collisions. So, while most people would have been only modestly injured, Ms. Kia was in the hospital for two months getting treatment for a broken leg and stress fractures to her back. None of the defendants were impressed when Ms. Kia sued for her full injuries and time off of work for the two-month period. Answer the following two questions.

QUESTION

1. What concept could Ms. Kia rely on to hold Amazon responsible for the driver's actions. Explain and apply that concept
2. Assume the driver was found completely liable for the accident. Would the driver be liable for paying for Ms. Kia's full injuries? Explain the legal concept in full.