Final answer:
Thomas Malthus concluded that the world's rate of population increase was higher than the development of food supplies, predicting unsustainable population levels without moral restraint leading to Malthusian disasters. The correct answer is b.
Step-by-step explanation:
Thomas Malthus concluded that B) the world's rate of population increase was higher than the development of food supplies. Malthus theorized that population growth occurs exponentially, while food production increases only arithmetically, predicting that without moral restraint, which includes measures like celibacy and birth control, populations would grow to levels unsustainable by the available food supplies, leading to consequences such as famine, disease, and war. These catastrophic events, termed as Malthusian disasters, act as 'positive checks' to increase mortality rates and keep the population in check. Conversely, 'preventive checks' aim to reduce population growth by lowering fertility rates.
Malthus's Malthusian theory has been subject to controversy and debate. Despite Malthus's dire predictions, factors like technological advances in food production, medical innovation, and the widespread use of contraception have allowed the human population to continue to grow. Neo-Malthusians and Cornucopians provide alternative perspectives on population growth and its sustainability.