Which of the following statements best describes the population trends seen in north africa today? a. population size is staying about the same, and the average age is about 40. b. populations are growing quickly, and there are growing numbers of children and young people. c. population size is declining throughout the region, and countries must care for growing numbers of elderly people. d. population size is staying about the same, and the average age is under 20. select the best answer from the choices provided a b c d