7) Consider the Malthusian model. Use its diagram to illustrate what happens to a country's population and per-capita income in the short and long run after each of the following events. Always also explain if this is a \"movement along the line\" or a \"movement of the line\". a) A discovery leads to a permanent increase in food yields. b) Climate change results in a permanent decrease in food yields. c) A sudden inux of refugees doubles the population. (1) Fertility preferences in the country change and people want to have fewer children for the same level of income