For most kids, it's time for back to school again, but for one Long Island fourth-grader, it feels more like "back to life" after receiving a heart transplant last Spring.Bowling Green Elementary in East Meadow gave 8-year-old Mahdi Islam a huge hero's welcome when he returned to his classroom Wednesday."I'm 500% happy!" said classmate Jayden Morkunas.Mahdi had lived his whole life with just one working ventricle in his heart. In 2016, his parents watched him endure six surgeries, while rapidly deteriorate."My dad, he's 75 years old, he was always praying, saying, 'God please take me, and give him back good health,'" said mom, Suhenez Islam, choking back tears.Then in April, their prayers were answered....