Question

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 populations is :
A. 10
B. 15
C. `05`
D. zero

Answer 1

Correct Answer - D
Natality = 250, Immigration = 20
Mortality = 240, Emigration = 30
Increase in Popolution size
P.D = [(Natality + Immigration) – (Mortality + Emigration)]
= [(250 + 20) – (240 + 30)]
= 0