Studies continue to prove that if a girl stays in school she will strengthen her family, community, and nation. A long list of benefits of educating a girl in a developing country compiled by the World Health Organization includes later marriages, smaller families, better hygiene, greatly increased likelihood that further children will receive education, and my favorite – greater confidence. A bicycle is a simple, sustainable tool that eases long travel distances and encourages girls to stay in school. —Foreword to Wheels of Change, Leah Missbach Day What is the central idea of this passage from the foreword?