Final Answer:
For Robert Malthus, societies with small populations were limited by the availability of resources, particularly food supply.
Step-by-step explanation:
Robert Malthus, an influential economist and demographer, proposed the theory of population growth in relation to available resources. According to Malthusian theory, societies with small populations were constrained by the limited availability of resources, especially food. He argued that the population tends to grow faster than the capacity of the land to produce food, leading to potential scarcity and checks on population growth.