Home
Class 12
BIOLOGY
A biologist studied the population of ra...

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

Text Solution

Verified by Experts

The correct Answer is:
D
Natality = 250, Immigration = 20
Mortality = 240, Emigration = 30
Increase in Popolution size
P.D = [(Natality + Immigration) – (Mortality + Emigration)]
= [(250 + 20) – (240 + 30)]
= 0
Promotional Banner

Topper's Solved these Questions

  • NEET

    NEET PREVIOUS YEAR (YEARWISE + CHAPTERWISE)|Exercise QUESTION|187 Videos

  • MORPHOLOGY OF FLOWERING PLANTS

    NEET PREVIOUS YEAR (YEARWISE + CHAPTERWISE)|Exercise Exercise|91 Videos

  • NEET 2018

    NEET PREVIOUS YEAR (YEARWISE + CHAPTERWISE)|Exercise Exercise|90 Videos

Similar Questions

Explore conceptually related problems

A biologist studied the population of rats in a barn. He found that the average natalty was 250, average mortality 240, immigration 20 and emigration 30. The net increase in populations is:

The given figure represents different factors affecting population density (N) . If B = natality D = mortality , E = emigration and I = immigration, then select the incorrect option regarding these.

Which of the following contributes to increase in population density ? (a) Natality (b) Mortality (c) Immigration (d) Emigration

Find the average increase rate if increase in the population in the first year is 30% and that in the second year is 40%.

Read the following information and five statements given below it carefully and answer the question which follow : Excerpt from a research report - 'Average life expectancy in southern part of India is far more than that in Western India. While the average life of a native of South India is 82 years, the average life of a native of Western India is only 74 years.' Based on the above fact, the proposal that the above study makes is that if an individual moves from Western India to South India, his/her life life expectancy would immediately increase by eight years. Which of the following statement would weaken the above-mentioned studies proposal that people belonging to Western parts of India should move to South India to increase their life expectancy ? 1) The average life expectancy of population living in Eastern part of the country is also less than the population living in South India. 2) Nearly 80% of the population in Southern India has a minimum age of 83 years 3) Higher life expectancy in Southern India can be ascribed to the genetic makeup of the population belonging to that area. 4) The average life expectancy of South India is comparable to the best averages in the world. 5) Higher life expectancy in the Southern India can be attributed to better environmental conditions and better healthcare facilities.

NEET PREVIOUS YEAR (YEARWISE + CHAPTERWISE)-NEET-MCQ
  1. Which one of the following is not the function of placenta?It:

    Text Solution

    |

  2. One of the legal methods of birth control is

    Text Solution

    |

  3. Which of the following cannot be detected in a developing foetus by am...

    Text Solution

    |

  4. Artificial insemination means

    Text Solution

    |

  5. Which Mendelian idea is depricted by a cross in which the "F"(1) gener...

    Text Solution

    |

  6. The incorrect statement with regard to haemophilia is

    Text Solution

    |

  7. If both parents are carriers for thalassaemia, which is an automal rec...

    Text Solution

    |

  8. The diagram shows an important concept in the genetic implication of D...

    Text Solution

    |

  9. Which enzyme/s will be produced in a cell in which there is a nonsese ...

    Text Solution

    |

  10. According of Darwin, the organic evolution is due to

    Text Solution

    |

  11. The eye of octopus and eye of cat show different patterns of structure...

    Text Solution

    |

  12. Infection of Ascaris usually occurs by :

    Text Solution

    |

  13. The cell-mediated immunity inside the human body is carried out by

    Text Solution

    |

  14. In plant breeding programme, the entire collection (of plants/seed) ha...

    Text Solution

    |

  15. During sewage treatment, biogases are produced which includes :

    Text Solution

    |

  16. A biologist studied the population of rats in a barn. He found that th...

    Text Solution

    |

  17. Which one of the following processes during decomposition is correctly...

    Text Solution

    |

  18. A sedentary sea anemone gets attached to the shell lining of hermit cr...

    Text Solution

    |

  19. Global warming can be controlled by:

    Text Solution

    |

  20. The Air Prevention and Control of Pollution Act came into force in:

    Text Solution

    |