She searched among the stacks and on the shelves. what is the object of the preposition among? she shelves stacks searched

Why it's time to lay the stereotype of the 'teen brain’ to rest 1. part a: which statement identifies the central idea of the text? a experts have spent time researching how different the teenage brain is from adults’ brains, when they are actually more similar than different. b teenagers often engage in risky behavior to fulfill the narrative they have been told about how teenagers are supposed to behave. c explanations for why teenagers engage in risky behavior have been overly focused on brain development, rather than their natural need to explore the world. d teenagers’ risky behavior is influenced by the combined effects of their hormone levels and their brain development.