Dear Student, Balancing the need of use resources & also to conserve them for the future is called a sustainable development. some principles of sustainable development are: 1. Respect and care all forms of life. 2. improve the quality of human life. 3. conserve the earth's vatility & diversity 4. minimise the use of natural resource. 5. change personal atitude & practices towards the environment. Reusing is better than recycle because : 1. Recycle needs some process to use the same material again. 2. Reuse save energy by using material again without any changes. 3. Reuse saves environmental pollution by not creating any waste. 4. Reuse saves cost as same material is used again with any process.