Why were some victims spared immediate death when they arrived at Auschwitz?

Some victims were spared immediate death upon arrival at Auschwitz due to the Nazis' systematic selection process. Individuals deemed fit for labor, such as those who were young, strong, or healthy, were often sent to work camps instead of being sent directly to the gas chambers. This practice allowed the Nazis to exploit these individuals for forced labor, contributing to their economic goals while prolonging the suffering of those who would ultimately face death later on.