... World development is the improvement in education, the environment & also health services.
Development is a measure of how rich or poor a country is. The reason why need development is because if the world isn’t improving in anyway there will be no progress and therefore there is no net result. If in poorer countries the percentage of people who are educated is low then the environment which is already in a bad state will remain in a bad state and the health services will also suffer. It is only if the world develops change will take place. There is a chain of links if one of these is weak the rest will be (e.g. if there is a lack of education or poor education then health services suffer, the environment and also less people will be able to get educated in the future because there will be few people who are able to teach others) ...