3.
Explain the four stages of the Demographic Transition Model in brief.
Answer: Stage 1: Both birth and death rates are high and population grows slowly, if at all (Europe between pre-history and about 1650).
Stage 2: Birthrates remain high, but death rates fall sharply as a result of improved nutrition, medicine, health care, and sanitation. Population begins to grow rapidly (began in Europe slowly after 1650, then more rapidly after the Industrial Revolution spread in the early 19th century).
Stage 3: Birthrates begin to drop rapidly, death rates continue to drop, but more slowly. Economic and social gains, combined with lower infant mortality, reduce the desire for large families (in Europe, birthrates in some nations began to fall in the 19th century and spread across the region by the early 20th century).
Stage 4: Both birth and death rates are in balance, but at a much lower rate; population growth is minimal if at all (Europe since the 1970s).