PBL provides an instructional approach that allows for differentiating instruction to meet individual student needs. It fosters development of content knowledge as well as skills like problem solving, collaboration, and self-evaluation. PBL naturally supports differentiated instruction through varying student roles and materials. Specifically, PBL targets students' zones of proximal development by providing challenging material that requires some assistance but is not frustrating. Teachers can guide students to readings matched to their reading level and background knowledge on a topic. PBL also capitalizes on student strengths by allowing them to learn in ways that suit their talents and intelligence, while still developing weaker skills.