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Organisms and Populations

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Biology

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Biology

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations. A and B twenty years apart. Select the correct interpretation about them

Interpretations

  • 'A' is more recent and shows slight reduction in the growth rate

  • 'B' is earlier pyramid and shows stabilised

  • 'B' is more recent showing that population is very young

  • 'A' is the earlier pyramid and no change has occurred in the growth rate


A.

'A' is more recent and shows slight reduction in the growth rate

Interpretation 'A' is correct for the given figures.

Interpretation 'A' is correct for the given figures.


Ants give information to their companions :
  • by dancing
  • by secretion of pheromones
  • by making sound
  • by defecating

B.

by secretion of pheromones

Population density is denoted by the symbol
  • N
  • D
  • M
  • D

A.

N

To live in groups is beneficial because :
  • feeling of security
  • can obtain food easily
  • Partner is available for mating
  • All the above

D.

All the above

The departure of a individual from a population is called :
  • Natality 
  • Mortality
  • Immigration 
  • Emigration

D.

Emigration

The number of births during a given period in the
population that are added to the initial density is 

 :
  • Natality
  • Mortality
  • Migration
  • Immigration

A.

Natality