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 :
- 15
- 05
- 10
- zero
Answer
(4) zero
Solution
Change in population density:
N = (B + I) - (D + E)
where B = natality, I = immigration, D = mortality, E = emigration.
⇒ N = (250 + 20) - (240 + 30)
= 270 - 270 = 0
∴ There is no net increase in the population.
Answer: (4)