Theravada - Death and rebirth

Recently I did my research and getting familiar with actual teachings of Buddha. Here are my questions. 2 : There are some kids who can/ could remember things from their past life. Could this be true? If it is true how come? And correct me if I'm wrong. According to my understanding, Everything including humans belongs to the nature. Human body is made of energies, atoms, molecules etc. When the body dies, those energies don't die with it. They take another form. Like the mango tree example. Thank you.