This set of Class 12 Biology Chapter 13 Multiple Choice Questions & Answers (MCQs) focuses on “Population Growth – 1”.
1. Which of the following process is responsible for fluctuation in population density?
a) Mimicry
b) Natality
c) Hibernation
d) Age structure
View Answer
Explanation: Natality is responsible for fluctuation in population density. It is the number of individuals born in a population at a specific time. For humans, it is described as a number of individuals born per 1000 of the population per year.
2. Which letter is used to designate the birth rate (Natality)?
a) B
b) E
c) I
d) K
View Answer
Explanation: Natality (birth rate) is designated by the letter ‘B’. It is the number of individuals born in a population at a specific time. For humans, it is described as a number of individuals born per 1000 of the population per year.
3. Which of the following correctly tells about population density at time t+1?
a) Nt + 1 = Nt + [(B + I) – (I + E)]
b) Nt + 1 = Nt + [(B + I) – (D + E)]
c) Nt + 1 = Nt + [(B + D) – (B + E)]
d) Nt + 1 = -Nt + [(B + I) – (D + E)]
View Answer
Explanation: The population density at time t+1 is given as Nt + 1 = Nt + [(B + I) – (D + E)]. Here Nt is population at time t, B is natality, I is immigration, D is mortality while E is emigration.
4. Which of the following process is responsible for fluctuation in population density?
a) Aestivation
b) Camouflage
c) Hibernation
d) Mortality
View Answer
Explanation: Mortality is responsible for fluctuation in population density. It is the number of individuals died in a population at a specific time. For humans, it is described as a number of deaths per 1000 of the population per year.
5. Which of the following is responsible for an increase in population density?
a) Age structure
b) Emigration is more
c) Immigration is more
d) Death rate increase
View Answer
Explanation: Population density increases when there is an increase in immigration. It is an act of coming into a different country of which they are not natives and reside permanently. This increases the population density of an area where they are residing.
6. Which letter is used to designate the death rate (Mortality)?
a) J
b) D
c) S
d) U
View Answer
Explanation: The mortality (death rate) is designated by ‘D’. It is the number of individuals died in a population at a specific time. For humans, it is described as a number of deaths per 1000 of the population per year.
7. Which of the following process is responsible for fluctuation in population density?
a) Hibernation
b) Aestivation
c) Mimicry
d) Immigration
View Answer
Explanation: Immigration is responsible for fluctuation in population density. It is an act of coming into a different country of which they are not natives and reside permanently. This increases the population density of an area where they are residing.
8. Which of the following is responsible for an increase in population density?
a) Death rate increase
b) Age structure
c) Birth rate increase
d) Emigration is more
View Answer
Explanation: The increase in birth rate (natality) is responsible for an increase in population density. Natality is the number of individuals born in a population at a specific time. The population density tells about the number of individuals in a unit area (per square meter, per square kilometer or per hectare) at a specific time.
9. Which letter is used to designate the immigration?
a) A
b) K
c) S
d) I
View Answer
Explanation: Immigration is designated by the letter ‘I’. Immigration is responsible for fluctuation in population density. It is an act of coming into a different country of which they are not natives and reside permanently.
10. Which of the following is responsible for a decrease in population density?
a) Birth rate increase
b) Immigration is more
c) Emigration is more
d) Age structure
View Answer
Explanation: The population density decreases when emigration is more. Emigration is an act of leaving one’s own country and settling or residing in another country (abroad) permanently.
11. Under normal conditions which of the following factor is responsible for influencing population density?
a) Pyramid
b) Births
c) Immigration
d) Emigration
View Answer
Explanation: Under normal conditions, the population density is influenced by births in an area at a specific time i.e. birth rate. The increase in birth rate (natality) is responsible for an increase in population density.
12. Under normal conditions which of the following factor is responsible for influencing population density?
a) Pyramid
b) Immigration
c) Deaths
d) Emigration
View Answer
Explanation: Under normal conditions, the population density is influenced by deaths in an area at a specific time i.e. death rate (mortality). It is the number of individuals died in a population at a specific time.
13. Which letter is used to designate the emigration?
a) J
b) E
c) U
d) V
View Answer
Explanation: The letter used to designate emigration is ‘E’. Emigration is an act of leaving one’s own country and settling or residing in another country (abroad) permanently.
14. Which of the following is responsible for a decrease in population density?
a) Birth rate increase
b) Immigration is more
c) Age structure
d) Death rate increase
View Answer
Explanation: The increase in death rate (mortality) is responsible for a decrease in population density. The death rate is the number of individuals died in a population at a specific time. The population density tells about the number of individuals in a unit area (per square meter, per square kilometer or per hectare) at a specific time.
15. Which of the following process is responsible for fluctuation in population density?
a) Emigration
b) Age structure
c) Mimicry
d) Camouflage
View Answer
Explanation: The emigration is responsible for fluctuation in population density. The population density decreases when emigration is more. Emigration is an act of leaving one’s own country and settling or residing in another country (abroad) permanently.
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