Answer : There are a number of things to consider when designing a sustainable building. First, you need to consider the materials you will use. Make sure to use recycled and recyclable materials where possible, and avoid using materials that will produce harmful toxins or pollutants. Second, you need to consider the energy needs of the building. Look into using renewable energy sources like solar and wind power, and make sure the building is well insulated to reduce heat loss. Third, water usage is another key factor in sustainability – try to use water-saving fixtures and limit the amount of landscaping that requires watering. Finally, waste management is important in any sustainable building – make sure there are recycling facilities available for tenants or residents to use.