Concept:Overcrowding develops when the number of individuals entering and surviving in a population is greater than the number leaving or dying.
Explanation:Rapid overcrowding is brought about by low mortality rate, high birth rate, high immigration rate, and low emigration rate.
A high birth rate supplies many new individuals.
A high immigration rate adds more individuals from other places.
A low mortality rate means fewer individuals are lost to death.
A low emigration rate means very few individuals leave the population.
Statement I represents the high birth and high immigration pair.
Statement II represents the low mortality and low emigration pair.
Together, these two statements contain all four conditions needed for rapid overcrowding.
Answer:D. I and II