Final answer:
Junior decides to transfer to Reardan High School in search of better education and opportunities, driven by a desire to escape the cycle of poverty and limited prospects on the reservation.
Step-by-step explanation:
In the novel The Absolutely True Diary of a Part-Time Indian by Sherman Alexie, the protagonist, Arnold Spirit Jr., also known as Junior, decides to transfer to Reardan High School for a number of reasons. His main motivation is the search for a better education and opportunities that he feels are not available at the school on his reservation. Junior believes that Reardan, a school with predominantly white students, can offer him higher academic standards, better textbooks, and enhanced possibilities for his future. Additionally, after confronting some harsh realities on the reservation, including the loss of his sister and witnessing the limited futures of those around him, he becomes determined to break free from the cycle of poverty and despair. He realizes that staying would likely lead to a life constrained by low expectations and few opportunities. This powerful desire for hope and change is what ultimately drives Junior to take the daunting step to leave what he knows behind and seek out a new path at Reardan High School.