Climate and economic development have a close relationship. In Europe, countries with a colder climate in the north are generally more developed than those in the south; in the Americas, Canada, and the United States, they are more developed than in the south of Mexico; in Asia, Korea's GDP is the sum of all Southeast Asian countries. So this difference is because people in cold regions will further complicate their brains in order to survive, while people in the tropics lose their motivation to further evolve due to adequate food. Which one of the following can most weaken the above argument? ['Human inertia resembles people everywhere.', 'People in cold regions are no better than tropical people.', 'There is no necessary connection between economic development and cultural prosperity.', 'Getting food is not the main mental activity of humans.']