Which of the following factors must account for the rapid increase in world population during the twentieth century?

The factor that best explains the rapid increase in world population during the twentieth century is the decrease in death rates. This is due to advances in medicine, improved sanitation, and better access to food and clean water. As people began to live longer and survive diseases that once were fatal, the population grew rapidly. While increasing world production of food did play a role, it was largely a result of the increase in population, rather than a cause. The abolition of the slave trade and large-scale migration of people did not have a significant impact on the overall population growth. Lastly, birth rates did increase in some regions, but not enough to account for the rapid increase in population without the decrease in death rates.