Chapter 37, Problem 1MCQ

Population size increases when

a. the sum of birth rate and death rate exceeds the sum of immigration and emigration.

b. the sum of birth rate and immigration exceeds the sum of death rate and emigration.

c. the sum of birth rate and emigration exceeds the sum of death rate and immigration.

d. the sum of death rate and immigration exceeds the sum of birth rate and emigration.

Summary Introduction

Introduction:

Population refers to all the organisms belonging to the same species living in a particular area. Basically, population can be simply referred to a group or collection of humans in a particular area. Population size changes with change in birth rate and death rate of individuals. It determines whether a population is increasing or decreasing.

Answer to Problem 1MCQ

Correct answer:

Population size is said to be increasing when birth rate and people immigrating are more than death rate and people emigrating. Therefore, option b. is correct.

Explanation of Solution

Reason for the correct statement:

Immigration refers to the movement of people into a particular area, whereas emigration refers to the movement of people, outside a particular area. So, when birth rate and immigration in a region are more than death rate and emigration, the population is said to be increasing.

Option b. is given as “the sum of birth rate and immigration exceeds the sum of death rate and emigration”.

As, “population size increases when immigration and birth rate exceeds emigration and death rate”, is the right answer.

Hence, option b. is correct.

Reasons for incorrect statements:

Option a. is given as “the sum of birth rate and date rate exceeds the sum of immigration and emigration”.

The birth rate should be higher than death rate for population size to increase. Similarly, number of immigrants should be more than number of emigrants for a population to increase. So, it is a wrong answer.

Option c. is given as “the sum of birth rate and emigration exceeds the sum of death rate and immigration”.

If people are emigrating, population size would reduce. So, it is a wrong answer.

Option d. is given as “the sum of death rate and immigration exceeds the sum of birth rate and emigration”.

Death rate should be lower than birth rate for a population size to increase. So, it is a wrong answer.

Hence, options a., c., and d. are incorrect.

Conclusion

Population size increases when people immigrating in an area and birth rate of that area are greater than the death rate and people emigrating from that area.