how does Salva change and grow as a character in chapter 12? what causes this change to happen?

Salva learns what it means to be a boy with no home just trying to survive. He becomes adept at taking care of himself. Salva realizes with a sinking heart that it is not his mother, and Uncle’s words come back to him. He seems to be standing on the precipice of a giant hole; he is completely alone. He remembers them all and wonders how he can go on. Then, though, he thinks of how Uncle guided him through the desert one step at a time and he decides he can get through life in camp the same way. He only has to get through this day, then the next. If someone had told him he’d be in Itang for six years, he would not have believed it.