Discussing Cause -1

  There has been a huge increase in population over the past 150 years.  As for what brings about this, several elements are included.  To begin with, because of the better sanitation, people won't be sick easily.  What's more, poeple nowadays have learned a lot about sanitation and have practiced well to prevent possible diseases or flu.  In addition, food plays an important role in people's daily life, and thanks to improved farming methods that produce more and better food, they enables people to digest various nutrients and provide people with strengh and energy.  Moreover, as a result of advances in medicine and health care, on feeling sick, people can go to the hospital for a health examination.  The earlier the illness is discovered, the sooner people can receive appropriate cure or undergo an operation.  Last but not the least, due to the improvement of sanitation, advanced technology, and other factors, fewer infant dies and more people live longer.  To sum up, based on what are mentioned above, they show several causes leading to the population increase.