However, education is not a magic bullet, and it faces many challenges in low- and middle-income countries, where poverty is most prevalent. Some of these challenges include the lack of access, quality, relevance, and equity of education, as well as the low returns, high costs, and external constraints that limit the impact of education on poverty reduction. For example, many poor children and youth do not have the opportunity to enroll or complete basic education, due to factors such as distance, fees, discrimination, violence, or child labor. Even if they do attend school, they may not receive adequate learning outcomes, due to factors such as overcrowded classrooms, poorly trained teachers, insufficient materials, or irrelevant curricula. Furthermore, even if they do acquire skills and knowledge, they may not be able to translate them into higher income or better livelihoods, due to factors such as low demand, low wages, unemployment, corruption, or conflict.