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 population is :

• A. 10
• B. 15
• C. 5
• D. Zero

Answer 1

The correct option is D Zero

In a community, the net increases in population = Birth rate + Immigration - Death rate - Emmigration.
In this question, natality or birth rate = 250
mortality or death rate = 240
immigration = 20
emmigration =30
Therefore net increase in population = 250 + 20 - 240 - 30 = 0
Therefore, there is no chage in the population.