Answer:
- B. It is happening today in the united states and europe.
- C. its happening today in most developing nations.
- D. Occured in the U.S and europe in the 19th century.
Step-by-step explanation:
- The demographic transition the movement of the population from a high birth and high death rate to low birth and low death rate of population growth.
- It began in the 19th century in the economically developed nations of the world.
- A large reduction in birth rates was followed by the early 20th century.
- The developing nations of the world are having large-scale population growth while the developed are declining.