How would I answer the long essay question?

There are many ways, but what examiners are looking for is factual knowledge. Have at least 2 case studies within the essay question; one to support your point and the other to show that there is another way. Explain why the case studies either support or falsify your thesis, and thus conclude. Do not only state facts though, explain what the facts mean, and why this information could came about. E.g 120000 deaths in Kenya occurred due to the malaria, and parents therefore began to have more children so some could survive the outbreak. This supports the thesis statement that mortality rates are higher in LEDCs.
You can also use more than two case studies, but remember to be concise with your writing, and conclude according to your thesis. Answer each part of the question, and define the key terms.