A biologist studied the population of rats in a barn. He found that the average natality was 250, average mortality 240, immigration 20 and emigration 30. The net increase in population is:
1. 15
2. 05
3. zero
4. 10
A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations. A and B are twenty years apart. Select the correct interpretation about them:
Interpretations
1. | 'A' is more recent and shows a slight reduction in the growth rate |
2. | 'B' is an earlier pyramid and shows stabilised growth rate |
3. | 'B' is more recent showing that the population is very young |
4. | 'A' is the earlier pyramid and no change has occurred in the growth rate |