【加賴叫過去】評論

The demographic transition took about 200 years to complete in Europe. Many developing countries are still in stage two of the demographic transition model: births far outstrip deaths. In these countries, CDR has declined due to improvements in sanitation and increases in food productivity, but the birth rate has still not adjusted downward to the new realities of improved living conditions. This imbalance of births over deaths in the developing world is the fundamental reason for the dramatic population explosion in the latter half of the twentieth century. However, population statistics indicate that in many less developed countries the CBRs have begun to decline over recent decades, giving rise to optimism in some quarters about future trends. The rapid industrialization of many parts of the developing world has meant that these countries have reached stage three of the model much faster than countries in the developed world did during the nineteenth century. This fact has led many demographers to predict that world population will reach an equilibrium level sooner and at a lower total than more pessimistic earlier predictions.選(A)