Heather Mills McCartney lives an admirable life, attending celebrity parties, meeting regularly with the rich and famous and doing meaningful work for charity. All who work with her admire and respect her. But Heather's life hasn't always been so easy. When Heather was only 9 years old, her mother abandoned her and her two brothers. At the age of 13, she ran away from home and ended up living on the streets in London. Eventually, however, her exceptional beauty led to a career in modeling. At that time, Heather also began helping with the war relief efforts in former Yugoslavia. Through her modeling and relief work, she soon became famous. But in August 1993, at age 25 her life changed once again. She was crossing the street in London when a motorcycle crashed into her. She was so badly injured that the doctors had to cut off her left leg. After that, she discovered she frequently needed to change her artificial limbs. It was expensive and she felt it was a waste to just throw away the old one. It occurred to her to set up an organization that could deliver used artificial limbs to Yugoslavia and other war-torn countries. It was through her charity  work that she met her husband Paul McCartney. Throughout her life, Heather has risen above problems and focused on helping others. Her work with artificial limbs even earned her a nomination  for the Nobel Peace Prize in 1996. Heather's persistence and determination are what impresses anyone who knows her. Heather believes anyone can make a positive difference in the world. From the passage we can infer that people admire and respect Heather because   _  .
she had a lot of misfortunes during her childhood. she was a world-famous model she is determined and never gives in she made a great difference in the world