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

15

B

5

C

10

D

zero

Text Solution

Verified by Experts

The correct Answer is:
D
Promotional Banner

Topper's Solved these Questions

  • POPULATION : INTERACTIONS AND ATTRIBUTES

    GRB PUBLICATION|Exercise NCERT Corner (Exemplar Problems)|32 Videos

  • PLANT BREEDING AND TISSUE CULTURE

    GRB PUBLICATION|Exercise NCERT CORNER|15 Videos

  • REPRODUCTION IN ORGANISMS

    GRB PUBLICATION|Exercise EXEMPLAR PROBLEMS|33 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.

GRB PUBLICATION-POPULATION : INTERACTIONS AND ATTRIBUTES-NCERT Corner (Exemplar Problems)
  1. A biologist studied the population of rats in a barn. He found that th...

    Text Solution

    |

  2. Autecology is the

    Text Solution

    |

  3. Ecotone is

    Text Solution

    |

  4. Biosphere is

    Text Solution

    |

  5. Ecological niche is

    Text Solution

    |

  6. According to Allen's Rule, the mammals from colder climates have

    Text Solution

    |

  7. Salt concentration (salinity) of the sea measured in parts per thousan...

    Text Solution

    |

  8. Formation of tropical forests needs mean annual temperature and mean a...

    Text Solution

    |

  9. Which of the following forest plants controls the light conditions at ...

    Text Solution

    |

  10. What will happen to a well growing herbaceous plant in the forest if i...

    Text Solution

    |

  11. If a population of 50 Paramecium present in a pool increases to 150 af...

    Text Solution

    |

  12. What would be the per cent growth or birth rate per individual per ho...

    Text Solution

    |

  13. A population has more young individuals compared to the older individu...

    Text Solution

    |

  14. What parameters are used for tiger census in our country's national pa...

    Text Solution

    |

  15. Which of the following would necessarily decrease the density of a pop...

    Text Solution

    |

  16. A protozoan reproduces by binary fission. What will be the number of p...

    Text Solution

    |

  17. In 2005, for each of the 14 million people present in a country, 0.028...

    Text Solution

    |

  18. Amensalism is an association between two species where :

    Text Solution

    |

  19. Lichens are the associations of :

    Text Solution

    |

  20. Which of the following is a partial root parasite ?

    Text Solution

    |

  21. Which pne of the following organisms reproduces sexually only once in ...

    Text Solution

    |