Their progress and wealth is highly dependent on the harvests, and the price of grain. They probably have to import some industrial products and if they had a bad year (weather, other catastrophies, poor technology) they can't get the necessary amount of industrial products in exchange for their surplus e. g. in grain. There are so many standards and requirements about the quality of food production that no country can survive solely on agriculture without high quality technology (machines, unharmful fertilizers, research-based breeding, etc.).
If resources get low, the population's numbers can decrease.
Answer: Development
Explanation: The human and natural resources in a developed area or country are brought to their full potential and to the benefit of the people who are citizens or residents there.
Development can be measured economically by the Gross Domestic Product GDP and by its effect on people through the Human Development Index HDI. While GDP measures the total goods and services produced, the HDI measures the level of education and opportunities available to people in the area or country.
