a) What are the key economic models that underpin the various economic growth theories? Give examples of how these models apply to developing countries. (7 Marks) b) Citing examples from most countries in Sub-Saharan Africa, describe the principal causes of high population growth in developing countries and the major consequences. (6 Marks) c) What is the relationship between the Lorenz curve and a Gini Coefficient? Give examples of how the Lorenz curve and Gini Coefficient can be used as summary measures of equality and inequality in a nation's distribution of income