Learners vary not only in their skills and abilities, but also in the kinds of challenges that motivate them to do their best work. All learners need to be challenged, but not always in the same way. In addition to providing appropriately varied levels and types of demands, learners also need to be provided with the right kinds of resources necessary for successful completion of the task. Learners cannot meet a demand without appropriate, and flexible, resources. Providing a range of demands, and a range of possible resources, allows all learners to find challenges that are optimally motivating. Balancing the resources available to meet the challenge is vital.