Break down of question: "named settlement" - needs an example that you can give particular facts on "sustainable" - consider in what sense the term is used. When thinking about urbanisation, the issue is often rapid growth. "system approach" - particular theory you need to apply - based on the model of imputs and outputs Looking for about an 8 line answer - 4 points that directly answer the question. 2 sentence that explain the systems approach through your example. An example might be Curitiba, Brazil. For example "Settlement sustainability, understood through the systems approach, measure the inputs (such as food, energy, goods) and outputs (pollution and waste) of a settlement. The fewer input by reusing what would be outputs makes a seetlement more sustainable. In Curitiba in Brazil, there are lots of cheap buses to reduce the number of cars on the road, which reduces the emissions of greenhouse gases. This reduces the city's output. Waste collectors can sell rubbish to recyclers for a profit so less goes into landfill sites. This also reduces output but also reduces the amount of inputs the city would have to source from else by reusing recycled goods. This increase sustainability in the local environment and the gloabl environment".