The world population growth rate in 2015 is about 1 percent. It is expected to drop to 0.5 percent by 2050, partly because of increased access to birth control in developing nations. Another likely cause for the expected decline is:
a. a decrease in the spread of pandemic diseases like Ebola
b. an increase in the total fertility rate in developed nations
c. an increased global food supply as a result of climate change
d. increasing numbers of women entering the workforce in developing nations
e. medical advances that will increase the life spans of people in developing nations