According to the passage, which of the following places are at a developmental disadvantage?

Landlocked countries, regions with diseases that are difficult to control or cure, and areas that are very far from major markets for their goods are all at a developmental disadvantage, and this disadvantage was probably greater in an earlier era, when medical knowledge was limited and transportation and communication costs were much higher. By virtue of weather and disease, tropical environments in particular may be less conducive to urbanization and industrialization than temperate zones. Some scholars ascribe a substantial portion of the developmental problems of tropical regions like sub-Saharan Africa to geography itself. But geographic factors cannot be the whole story, as there is a great deal of variation among countries within the same regions. If we compare less developed countries that have very similar geographic characteristics, we find that some have done extremely well, while others have done very poorly. While the climate and geography of a nation shape its development, they do so through their impact on the people, social structures, politics, and policies of the nation.